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[Qemu-devel] [PATCH 01/26] tcg-aarch64: Properly detect SIGSEGV writes
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 01/26] tcg-aarch64: Properly detect SIGSEGV writes |
Date: |
Fri, 14 Mar 2014 19:48:27 -0700 |
Since the kernel doesn't pass any info on the reason for the fault,
disassemble the instruction to detect a store.
Signed-off-by: Richard Henderson <address@hidden>
---
user-exec.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)
diff --git a/user-exec.c b/user-exec.c
index bc58056..4c0cd46 100644
--- a/user-exec.c
+++ b/user-exec.c
@@ -465,16 +465,33 @@ int cpu_signal_handler(int host_signum, void *pinfo,
#elif defined(__aarch64__)
-int cpu_signal_handler(int host_signum, void *pinfo,
- void *puc)
+int cpu_signal_handler(int host_signum, void *pinfo, void *puc)
{
siginfo_t *info = pinfo;
struct ucontext *uc = puc;
- uint64_t pc;
- int is_write = 0; /* XXX how to determine? */
+ uintptr_t pc = uc->uc_mcontext.pc;
+ uint32_t insn = *(uint32_t *)pc;
+ bool is_write;
- pc = uc->uc_mcontext.pc;
- return handle_cpu_signal(pc, (uint64_t)info->si_addr,
+ /* XXX: need kernel patch to get write flag faster. */
+ /* XXX: several of these could be combined. */
+ is_write = ( (insn & 0xbfff0000) == 0x0c000000 /* C3.3.1 */
+ || (insn & 0xbfe00000) == 0x0c800000 /* C3.3.2 */
+ || (insn & 0xbfff0000) == 0x0d000000 /* C3.3.3 */
+ || (insn & 0xbfe00000) == 0x0d800000 /* C3.3.4 */
+ || (insn & 0x3f400000) == 0x08000000 /* C3.3.6 */
+ || (insn & 0x3bc00000) == 0x28400000 /* C3.3.7 */
+ || (insn & 0x3be00c00) == 0x38000400 /* C3.3.8 */
+ || (insn & 0x3be00c00) == 0x38000c00 /* C3.3.9 */
+ || (insn & 0x3be00c00) == 0x38200800 /* C3.3.10 */
+ || (insn & 0x3be00c00) == 0x38000800 /* C3.3.11 */
+ || (insn & 0x3be00c00) == 0x38000000 /* C3.3.12 */
+ || (insn & 0x3bc00000) == 0x39000000 /* C3.3.13 */
+ || (insn & 0x3bc00000) == 0x29000000 /* C3.3.14 */
+ || (insn & 0x3bc00000) == 0x28800000 /* C3.3.15 */
+ || (insn & 0x3bc00000) == 0x29800000); /* C3.3.16 */
+
+ return handle_cpu_signal(pc, (uintptr_t)info->si_addr,
is_write, &uc->uc_sigmask, puc);
}
--
1.8.5.3