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@@ -1,6 +1,4 @@
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/*
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/*
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- * linux/arch/x86-64/mm/fault.c
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- *
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* Copyright (C) 1995 Linus Torvalds
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* Copyright (C) 1995 Linus Torvalds
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* Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.
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* Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.
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*/
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*/
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@@ -33,16 +31,23 @@
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#include <asm/proto.h>
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#include <asm/proto.h>
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#include <asm-generic/sections.h>
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#include <asm-generic/sections.h>
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-/* Page fault error code bits */
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-#define PF_PROT (1<<0) /* or no page found */
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+/*
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+ * Page fault error code bits
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+ * bit 0 == 0 means no page found, 1 means protection fault
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+ * bit 1 == 0 means read, 1 means write
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+ * bit 2 == 0 means kernel, 1 means user-mode
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+ * bit 3 == 1 means use of reserved bit detected
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+ * bit 4 == 1 means fault was an instruction fetch
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+ */
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+#define PF_PROT (1<<0)
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#define PF_WRITE (1<<1)
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#define PF_WRITE (1<<1)
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#define PF_USER (1<<2)
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#define PF_USER (1<<2)
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#define PF_RSVD (1<<3)
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#define PF_RSVD (1<<3)
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#define PF_INSTR (1<<4)
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#define PF_INSTR (1<<4)
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-#ifdef CONFIG_KPROBES
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static inline int notify_page_fault(struct pt_regs *regs)
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static inline int notify_page_fault(struct pt_regs *regs)
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{
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{
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+#ifdef CONFIG_KPROBES
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int ret = 0;
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int ret = 0;
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/* kprobe_running() needs smp_processor_id() */
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/* kprobe_running() needs smp_processor_id() */
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@@ -54,75 +59,75 @@ static inline int notify_page_fault(struct pt_regs *regs)
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}
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}
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return ret;
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return ret;
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-}
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#else
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#else
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-static inline int notify_page_fault(struct pt_regs *regs)
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-{
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return 0;
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return 0;
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-}
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#endif
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#endif
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+}
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/* Sometimes the CPU reports invalid exceptions on prefetch.
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/* Sometimes the CPU reports invalid exceptions on prefetch.
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Check that here and ignore.
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Check that here and ignore.
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Opcode checker based on code by Richard Brunner */
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Opcode checker based on code by Richard Brunner */
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static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr,
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static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr,
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unsigned long error_code)
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unsigned long error_code)
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-{
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+{
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unsigned char *instr;
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unsigned char *instr;
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int scan_more = 1;
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int scan_more = 1;
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- int prefetch = 0;
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+ int prefetch = 0;
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unsigned char *max_instr;
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unsigned char *max_instr;
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/* If it was a exec fault ignore */
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/* If it was a exec fault ignore */
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if (error_code & PF_INSTR)
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if (error_code & PF_INSTR)
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return 0;
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return 0;
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-
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+
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instr = (unsigned char __user *)convert_rip_to_linear(current, regs);
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instr = (unsigned char __user *)convert_rip_to_linear(current, regs);
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max_instr = instr + 15;
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max_instr = instr + 15;
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if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE)
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if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE)
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return 0;
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return 0;
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- while (scan_more && instr < max_instr) {
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+ while (scan_more && instr < max_instr) {
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unsigned char opcode;
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unsigned char opcode;
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unsigned char instr_hi;
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unsigned char instr_hi;
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unsigned char instr_lo;
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unsigned char instr_lo;
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if (probe_kernel_address(instr, opcode))
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if (probe_kernel_address(instr, opcode))
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- break;
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+ break;
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- instr_hi = opcode & 0xf0;
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- instr_lo = opcode & 0x0f;
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+ instr_hi = opcode & 0xf0;
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+ instr_lo = opcode & 0x0f;
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instr++;
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instr++;
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- switch (instr_hi) {
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+ switch (instr_hi) {
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case 0x20:
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case 0x20:
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case 0x30:
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case 0x30:
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- /* Values 0x26,0x2E,0x36,0x3E are valid x86
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- prefixes. In long mode, the CPU will signal
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- invalid opcode if some of these prefixes are
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- present so we will never get here anyway */
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+ /*
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+ * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.
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+ * In X86_64 long mode, the CPU will signal invalid
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+ * opcode if some of these prefixes are present so
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+ * X86_64 will never get here anyway
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+ */
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scan_more = ((instr_lo & 7) == 0x6);
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scan_more = ((instr_lo & 7) == 0x6);
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break;
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break;
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-
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+#ifdef CONFIG_X86_64
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case 0x40:
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case 0x40:
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- /* In AMD64 long mode, 0x40 to 0x4F are valid REX prefixes
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- Need to figure out under what instruction mode the
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- instruction was issued ... */
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- /* Could check the LDT for lm, but for now it's good
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- enough to assume that long mode only uses well known
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- segments or kernel. */
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+ /*
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+ * In AMD64 long mode 0x40..0x4F are valid REX prefixes
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+ * Need to figure out under what instruction mode the
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+ * instruction was issued. Could check the LDT for lm,
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+ * but for now it's good enough to assume that long
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+ * mode only uses well known segments or kernel.
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+ */
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scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS);
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scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS);
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break;
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break;
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-
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+#endif
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case 0x60:
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case 0x60:
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/* 0x64 thru 0x67 are valid prefixes in all modes. */
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/* 0x64 thru 0x67 are valid prefixes in all modes. */
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scan_more = (instr_lo & 0xC) == 0x4;
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scan_more = (instr_lo & 0xC) == 0x4;
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- break;
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+ break;
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case 0xF0:
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case 0xF0:
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/* 0xF0, 0xF2, and 0xF3 are valid prefixes in all modes. */
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/* 0xF0, 0xF2, and 0xF3 are valid prefixes in all modes. */
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scan_more = !instr_lo || (instr_lo>>1) == 1;
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scan_more = !instr_lo || (instr_lo>>1) == 1;
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- break;
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+ break;
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case 0x00:
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case 0x00:
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/* Prefetch instruction is 0x0F0D or 0x0F18 */
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/* Prefetch instruction is 0x0F0D or 0x0F18 */
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scan_more = 0;
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scan_more = 0;
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@@ -130,20 +135,20 @@ static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr,
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break;
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break;
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prefetch = (instr_lo == 0xF) &&
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prefetch = (instr_lo == 0xF) &&
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(opcode == 0x0D || opcode == 0x18);
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(opcode == 0x0D || opcode == 0x18);
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- break;
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+ break;
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default:
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default:
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scan_more = 0;
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scan_more = 0;
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break;
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break;
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- }
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+ }
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}
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}
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return prefetch;
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return prefetch;
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}
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}
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-static int bad_address(void *p)
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-{
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+static int bad_address(void *p)
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+{
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unsigned long dummy;
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unsigned long dummy;
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return probe_kernel_address((unsigned long *)p, dummy);
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return probe_kernel_address((unsigned long *)p, dummy);
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-}
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+}
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void dump_pagetable(unsigned long address)
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void dump_pagetable(unsigned long address)
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{
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{
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@@ -154,11 +159,11 @@ void dump_pagetable(unsigned long address)
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pgd = (pgd_t *)read_cr3();
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pgd = (pgd_t *)read_cr3();
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- pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
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+ pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
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pgd += pgd_index(address);
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pgd += pgd_index(address);
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if (bad_address(pgd)) goto bad;
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if (bad_address(pgd)) goto bad;
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printk("PGD %lx ", pgd_val(*pgd));
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printk("PGD %lx ", pgd_val(*pgd));
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- if (!pgd_present(*pgd)) goto ret;
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+ if (!pgd_present(*pgd)) goto ret;
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pud = pud_offset(pgd, address);
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pud = pud_offset(pgd, address);
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if (bad_address(pud)) goto bad;
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if (bad_address(pud)) goto bad;
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@@ -172,7 +177,7 @@ void dump_pagetable(unsigned long address)
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pte = pte_offset_kernel(pmd, address);
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pte = pte_offset_kernel(pmd, address);
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if (bad_address(pte)) goto bad;
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if (bad_address(pte)) goto bad;
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- printk("PTE %lx", pte_val(*pte));
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+ printk("PTE %lx", pte_val(*pte));
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ret:
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ret:
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printk("\n");
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printk("\n");
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return;
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return;
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@@ -180,7 +185,7 @@ bad:
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printk("BAD\n");
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printk("BAD\n");
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}
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}
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-static const char errata93_warning[] =
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+static const char errata93_warning[] =
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KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
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KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
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KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
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KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
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KERN_ERR "******* Please consider a BIOS update.\n"
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KERN_ERR "******* Please consider a BIOS update.\n"
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@@ -188,31 +193,31 @@ KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
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/* Workaround for K8 erratum #93 & buggy BIOS.
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/* Workaround for K8 erratum #93 & buggy BIOS.
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BIOS SMM functions are required to use a specific workaround
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BIOS SMM functions are required to use a specific workaround
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- to avoid corruption of the 64bit RIP register on C stepping K8.
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- A lot of BIOS that didn't get tested properly miss this.
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+ to avoid corruption of the 64bit RIP register on C stepping K8.
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+ A lot of BIOS that didn't get tested properly miss this.
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The OS sees this as a page fault with the upper 32bits of RIP cleared.
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The OS sees this as a page fault with the upper 32bits of RIP cleared.
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Try to work around it here.
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Try to work around it here.
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Note we only handle faults in kernel here. */
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Note we only handle faults in kernel here. */
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-static int is_errata93(struct pt_regs *regs, unsigned long address)
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+static int is_errata93(struct pt_regs *regs, unsigned long address)
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{
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{
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static int warned;
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static int warned;
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if (address != regs->ip)
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if (address != regs->ip)
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return 0;
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return 0;
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- if ((address >> 32) != 0)
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+ if ((address >> 32) != 0)
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return 0;
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return 0;
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address |= 0xffffffffUL << 32;
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address |= 0xffffffffUL << 32;
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- if ((address >= (u64)_stext && address <= (u64)_etext) ||
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- (address >= MODULES_VADDR && address <= MODULES_END)) {
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+ if ((address >= (u64)_stext && address <= (u64)_etext) ||
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+ (address >= MODULES_VADDR && address <= MODULES_END)) {
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if (!warned) {
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if (!warned) {
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- printk(errata93_warning);
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+ printk(errata93_warning);
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warned = 1;
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warned = 1;
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}
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}
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regs->ip = address;
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regs->ip = address;
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return 1;
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return 1;
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}
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}
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return 0;
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return 0;
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-}
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+}
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static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
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static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
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unsigned long error_code)
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unsigned long error_code)
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@@ -296,7 +301,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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{
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{
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struct task_struct *tsk;
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struct task_struct *tsk;
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struct mm_struct *mm;
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struct mm_struct *mm;
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- struct vm_area_struct * vma;
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+ struct vm_area_struct *vma;
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unsigned long address;
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unsigned long address;
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int write, fault;
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int write, fault;
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unsigned long flags;
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unsigned long flags;
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@@ -360,8 +365,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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pgtable_bad(address, regs, error_code);
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pgtable_bad(address, regs, error_code);
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/*
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/*
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- * If we're in an interrupt or have no user
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- * context, we must not take the fault..
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+ * If we're in an interrupt, have no user context or are running in an
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+ * atomic region then we must not take the fault.
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*/
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*/
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if (unlikely(in_atomic() || !mm))
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if (unlikely(in_atomic() || !mm))
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goto bad_area_nosemaphore;
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goto bad_area_nosemaphore;
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@@ -403,7 +408,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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goto good_area;
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goto good_area;
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if (!(vma->vm_flags & VM_GROWSDOWN))
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if (!(vma->vm_flags & VM_GROWSDOWN))
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goto bad_area;
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goto bad_area;
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- if (error_code & 4) {
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+ if (error_code & PF_USER) {
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/* Allow userspace just enough access below the stack pointer
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/* Allow userspace just enough access below the stack pointer
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* to let the 'enter' instruction work.
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* to let the 'enter' instruction work.
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*/
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*/
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@@ -420,18 +425,18 @@ good_area:
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info.si_code = SEGV_ACCERR;
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info.si_code = SEGV_ACCERR;
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write = 0;
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write = 0;
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switch (error_code & (PF_PROT|PF_WRITE)) {
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switch (error_code & (PF_PROT|PF_WRITE)) {
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- default: /* 3: write, present */
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- /* fall through */
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- case PF_WRITE: /* write, not present */
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- if (!(vma->vm_flags & VM_WRITE))
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- goto bad_area;
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- write++;
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- break;
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- case PF_PROT: /* read, present */
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+ default: /* 3: write, present */
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+ /* fall through */
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+ case PF_WRITE: /* write, not present */
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+ if (!(vma->vm_flags & VM_WRITE))
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+ goto bad_area;
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+ write++;
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+ break;
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+ case PF_PROT: /* read, present */
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+ goto bad_area;
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+ case 0: /* read, not present */
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+ if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
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goto bad_area;
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goto bad_area;
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- case 0: /* read, not present */
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- if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
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- goto bad_area;
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}
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}
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/*
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/*
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@@ -491,7 +496,7 @@ bad_area_nosemaphore:
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tsk->comm, tsk->pid, address, regs->ip,
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tsk->comm, tsk->pid, address, regs->ip,
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regs->sp, error_code);
|
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regs->sp, error_code);
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}
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}
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-
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+
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tsk->thread.cr2 = address;
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tsk->thread.cr2 = address;
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/* Kernel addresses are always protection faults */
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/* Kernel addresses are always protection faults */
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tsk->thread.error_code = error_code | (address >= TASK_SIZE);
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tsk->thread.error_code = error_code | (address >= TASK_SIZE);
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@@ -505,21 +510,19 @@ bad_area_nosemaphore:
|
|
}
|
|
}
|
|
|
|
|
|
no_context:
|
|
no_context:
|
|
-
|
|
|
|
/* Are we prepared to handle this kernel fault? */
|
|
/* Are we prepared to handle this kernel fault? */
|
|
- if (fixup_exception(regs)) {
|
|
|
|
|
|
+ if (fixup_exception(regs))
|
|
return;
|
|
return;
|
|
- }
|
|
|
|
|
|
|
|
- /*
|
|
|
|
|
|
+ /*
|
|
* Hall of shame of CPU/BIOS bugs.
|
|
* Hall of shame of CPU/BIOS bugs.
|
|
*/
|
|
*/
|
|
|
|
|
|
- if (is_prefetch(regs, address, error_code))
|
|
|
|
- return;
|
|
|
|
|
|
+ if (is_prefetch(regs, address, error_code))
|
|
|
|
+ return;
|
|
|
|
|
|
if (is_errata93(regs, address))
|
|
if (is_errata93(regs, address))
|
|
- return;
|
|
|
|
|
|
+ return;
|
|
|
|
|
|
/*
|
|
/*
|
|
* Oops. The kernel tried to access some bad page. We'll have to
|
|
* Oops. The kernel tried to access some bad page. We'll have to
|
|
@@ -532,7 +535,7 @@ no_context:
|
|
printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
|
|
printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
|
|
else
|
|
else
|
|
printk(KERN_ALERT "Unable to handle kernel paging request");
|
|
printk(KERN_ALERT "Unable to handle kernel paging request");
|
|
- printk(" at %016lx RIP: \n" KERN_ALERT,address);
|
|
|
|
|
|
+ printk(" at %016lx RIP: \n" KERN_ALERT, address);
|
|
printk_address(regs->ip);
|
|
printk_address(regs->ip);
|
|
dump_pagetable(address);
|
|
dump_pagetable(address);
|
|
tsk->thread.cr2 = address;
|
|
tsk->thread.cr2 = address;
|
|
@@ -582,7 +585,7 @@ LIST_HEAD(pgd_list);
|
|
|
|
|
|
void vmalloc_sync_all(void)
|
|
void vmalloc_sync_all(void)
|
|
{
|
|
{
|
|
- /* Note that races in the updates of insync and start aren't
|
|
|
|
|
|
+ /* Note that races in the updates of insync and start aren't
|
|
problematic:
|
|
problematic:
|
|
insync can only get set bits added, and updates to start are only
|
|
insync can only get set bits added, and updates to start are only
|
|
improving performance (without affecting correctness if undone). */
|
|
improving performance (without affecting correctness if undone). */
|
|
@@ -614,6 +617,6 @@ void vmalloc_sync_all(void)
|
|
}
|
|
}
|
|
/* Check that there is no need to do the same for the modules area. */
|
|
/* Check that there is no need to do the same for the modules area. */
|
|
BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
|
|
BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
|
|
- BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
|
|
|
|
|
|
+ BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
|
|
(__START_KERNEL & PGDIR_MASK)));
|
|
(__START_KERNEL & PGDIR_MASK)));
|
|
}
|
|
}
|