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authorRichard Henderson <rth@twiddle.net>2014-03-14 22:24:57 -0400
committerRichard Henderson <rth@redhat.com>2014-04-16 12:12:32 -0400
commit661f7fa4b088f2734050a751dd9d1d836b49e981 (patch)
tree94e0c8058361948716e71922bceedfd5243b00df /user-exec.c
parent851627352c52b5beebf119785885391fa05a44c5 (diff)
tcg-aarch64: Properly detect SIGSEGV writes
Since the kernel doesn't pass any info on the reason for the fault, disassemble the instruction to detect a store. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com> Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'user-exec.c')
-rw-r--r--user-exec.c25
1 files changed, 19 insertions, 6 deletions
diff --git a/user-exec.c b/user-exec.c
index bc58056e6c..8ed6fec814 100644
--- a/user-exec.c
+++ b/user-exec.c
@@ -465,16 +465,29 @@ 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. */
+ is_write = ( (insn & 0xbfff0000) == 0x0c000000 /* C3.3.1 */
+ || (insn & 0xbfe00000) == 0x0c800000 /* C3.3.2 */
+ || (insn & 0xbfdf0000) == 0x0d000000 /* C3.3.3 */
+ || (insn & 0xbfc00000) == 0x0d800000 /* C3.3.4 */
+ || (insn & 0x3f400000) == 0x08000000 /* C3.3.6 */
+ || (insn & 0x3bc00000) == 0x39000000 /* C3.3.13 */
+ || (insn & 0x3fc00000) == 0x3d800000 /* ... 128bit */
+ /* Ingore bits 10, 11 & 21, controlling indexing. */
+ || (insn & 0x3bc00000) == 0x38000000 /* C3.3.8-12 */
+ || (insn & 0x3fe00000) == 0x3c800000 /* ... 128bit */
+ /* Ignore bits 23 & 24, controlling indexing. */
+ || (insn & 0x3a400000) == 0x28000000); /* C3.3.7,14-16 */
+
+ return handle_cpu_signal(pc, (uintptr_t)info->si_addr,
is_write, &uc->uc_sigmask, puc);
}