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target-i386: fix crash on x86 32bit linux host with hw breakpoint exceptions

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If you make use of hw breakpoints on a 32bit x86 linux host, qemu
will segmentation fault when processing the exception.

The problem is that the value of env is stored in $ebp in the op_helper
raise_exception() function, and it can have the wrong value when
calling it from non generated code.

It is possible to work around the problem by restoring the value of
env before calling raise_exception() using a new helper function that
takes (CPUState *) as one of the arguments.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Jason Wessel 2010-01-26 16:29:50 -06:00 committed by Aurelien Jarno
parent 6049f4f831
commit 63a54736f3
3 changed files with 9 additions and 3 deletions
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1
target-i386/exec.h
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@ -73,6 +73,7 @@ void do_interrupt_user(int intno, int is_int, int error_code,
target_ulong next_eip);
void QEMU_NORETURN raise_exception_err(int exception_index, int error_code);
void QEMU_NORETURN raise_exception(int exception_index);
void QEMU_NORETURN raise_exception_env(int exception_index, CPUState *nenv);
void do_smm_enter(void);
/* n must be a constant to be efficient */

6
target-i386/helper.c
View File

@ -1862,7 +1862,7 @@ int check_hw_breakpoints(CPUState *env, int force_dr6_update)
static CPUDebugExcpHandler *prev_debug_excp_handler;
void raise_exception(int exception_index);
void raise_exception_env(int exception_index, CPUState *env);
static void breakpoint_handler(CPUState *env)
{
@ -1872,7 +1872,7 @@ static void breakpoint_handler(CPUState *env)
if (env->watchpoint_hit->flags & BP_CPU) {
env->watchpoint_hit = NULL;
if (check_hw_breakpoints(env, 0))
raise_exception(EXCP01_DB);
raise_exception_env(EXCP01_DB, env);
else
cpu_resume_from_signal(env, NULL);
}
@ -1881,7 +1881,7 @@ static void breakpoint_handler(CPUState *env)
if (bp->pc == env->eip) {
if (bp->flags & BP_CPU) {
check_hw_breakpoints(env, 1);
raise_exception(EXCP01_DB);
raise_exception_env(EXCP01_DB, env);
}
break;
}

5
target-i386/op_helper.c
View File

@ -1351,6 +1351,11 @@ void raise_exception(int exception_index)
raise_interrupt(exception_index, 0, 0, 0);
}
void raise_exception_env(int exception_index, CPUState *nenv)
{
env = nenv;
raise_exception(exception_index);
}
/* SMM support */
#if defined(CONFIG_USER_ONLY)