[PATCH 5/7] x86: traps_xx: restructure do_general_protection()

Alexander van Heukelum
2008-07-01T23:35:58Z

- if (cond) block -> if (!cond) goto end_of_block
- local caching of current

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
arch/x86/kernel/traps_32.c | 36 ++++++++++++++++++++----------------
arch/x86/kernel/traps_64.c | 41 ++++++++++++++++++++++-------------------
2 files changed, 42 insertions(+), 35 deletions(-)

diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index 9ed060e..68e800f 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -602,8 +602,10 @@ DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0, 0)
DO_ERROR_INFO(32, SIGILL, "iret exception", iret_error, ILL_BADSTK, 0, 1)

-void __kprobes do_general_protection(struct pt_regs *regs, long error_code)
+void __kprobes
+do_general_protection(struct pt_regs *regs, long error_code)
{
+ struct task_struct *tsk;
struct thread_struct *thread;
struct tss_struct *tss;
int cpu;
@@ -644,23 +646,24 @@ void __kprobes do_general_protection(struct pt_regs *regs, long error_code)
if (regs->flags & X86_VM_MASK)
goto gp_in_vm86;

+ tsk = current;
if (!user_mode(regs))
goto gp_in_kernel;

- current->thread.error_code = error_code;
- current->thread.trap_no = 13;
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = 13;

- if (show_unhandled_signals && unhandled_signal(current, SIGSEGV) &&
- printk_ratelimit()) {
+ if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
+ printk_ratelimit()) {
printk(KERN_INFO
- "%s[%d] general protection ip:%lx sp:%lx error:%lx",
- current->comm, task_pid_nr(current),
- regs->ip, regs->sp, error_code);
+ "%s[%d] general protection ip:%lx sp:%lx error:%lx",
+ tsk->comm, task_pid_nr(tsk),
+ regs->ip, regs->sp, error_code);
print_vma_addr(" in ", regs->ip);
printk("\n");
}

- force_sig(SIGSEGV, current);
+ force_sig(SIGSEGV, tsk);
return;

gp_in_vm86:
@@ -669,14 +672,15 @@ gp_in_vm86:
return;

gp_in_kernel:
- if (!fixup_exception(regs)) {
- current->thread.error_code = error_code;
- current->thread.trap_no = 13;
- if (notify_die(DIE_GPF, "general protection fault", regs,
+ if (fixup_exception(regs))
+ return;
+
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = 13;
+ if (notify_die(DIE_GPF, "general protection fault", regs,
error_code, 13, SIGSEGV) == NOTIFY_STOP)
- return;
- die("general protection fault", regs, error_code);
- }
+ return;
+ die("general protection fault", regs, error_code);
}

static notrace __kprobes void
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index b49c886..677b4e5 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -738,31 +738,34 @@ asmlinkage void do_double_fault(struct pt_regs * regs, long error_code)
die(str, regs, error_code);
}

-asmlinkage void __kprobes do_general_protection(struct pt_regs * regs,
- long error_code)
+asmlinkage void __kprobes
+do_general_protection(struct pt_regs *regs, long error_code)
{
- struct task_struct *tsk = current;
+ struct task_struct *tsk;

conditional_sti(regs);

- if (user_mode(regs)) {
- tsk->thread.error_code = error_code;
- tsk->thread.trap_no = 13;
-
- if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
- printk_ratelimit()) {
- printk(KERN_INFO
- "%s[%d] general protection ip:%lx sp:%lx error:%lx",
- tsk->comm, tsk->pid,
- regs->ip, regs->sp, error_code);
- print_vma_addr(" in ", regs->ip);
- printk("\n");
- }
+ tsk = current;
+ if (!user_mode(regs))
+ goto gp_in_kernel;

- force_sig(SIGSEGV, tsk);
- return;
- }
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = 13;
+
+ if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
+ printk_ratelimit()) {
+ printk(KERN_INFO
+ "%s[%d] general protection ip:%lx sp:%lx error:%lx",
+ tsk->comm, tsk->pid,
+ regs->ip, regs->sp, error_code);
+ print_vma_addr(" in ", regs->ip);
+ printk("\n");
+ }
+
+ force_sig(SIGSEGV, tsk);
+ return;

+gp_in_kernel:
if (fixup_exception(regs))
return;

--
1.5.4.3