diff options
| -rw-r--r-- | arch/x86/kernel/ftrace_32.S | 40 |
1 files changed, 21 insertions, 19 deletions
diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S index a4e2872971c0..93e26647c3f2 100644 --- a/arch/x86/kernel/ftrace_32.S +++ b/arch/x86/kernel/ftrace_32.S @@ -54,23 +54,27 @@ WEAK(ftrace_stub) END(ftrace_caller) ENTRY(ftrace_regs_caller) - pushf /* push flags before compare (in cs location) */ - /* * i386 does not save SS and ESP when coming from kernel. * Instead, to get sp, ®s->sp is used (see ptrace.h). * Unfortunately, that means eflags must be at the same location * as the current return ip is. We move the return ip into the - * ip location, and move flags into the return ip location. + * regs->ip location, and move flags into the return ip location. */ - pushl 4(%esp) /* save return ip into ip slot */ - + pushl $__KERNEL_CS + pushl 4(%esp) /* Save the return ip */ pushl $0 /* Load 0 into orig_ax */ pushl %gs pushl %fs pushl %es pushl %ds pushl %eax + + /* Get flags and place them into the return ip slot */ + pushf + popl %eax + movl %eax, 8*4(%esp) + pushl %ebp pushl %edi pushl %esi @@ -78,11 +82,6 @@ ENTRY(ftrace_regs_caller) pushl %ecx pushl %ebx - movl 13*4(%esp), %eax /* Get the saved flags */ - movl %eax, 14*4(%esp) /* Move saved flags into regs->flags location */ - /* clobbering return ip */ - movl $__KERNEL_CS, 13*4(%esp) - movl 12*4(%esp), %eax /* Load ip (1st parameter) */ subl $MCOUNT_INSN_SIZE, %eax /* Adjust ip */ movl 0x4(%ebp), %edx /* Load parent ip (2nd parameter) */ @@ -93,10 +92,14 @@ GLOBAL(ftrace_regs_call) call ftrace_stub addl $4, %esp /* Skip pt_regs */ - movl 14*4(%esp), %eax /* Move flags back into cs */ - movl %eax, 13*4(%esp) /* Needed to keep addl from modifying flags */ - movl 12*4(%esp), %eax /* Get return ip from regs->ip */ - movl %eax, 14*4(%esp) /* Put return ip back for ret */ + + /* restore flags */ + push 14*4(%esp) + popf + + /* Move return ip back to its original location */ + movl 12*4(%esp), %eax + movl %eax, 14*4(%esp) popl %ebx popl %ecx @@ -109,12 +112,11 @@ GLOBAL(ftrace_regs_call) popl %es popl %fs popl %gs - addl $8, %esp /* Skip orig_ax and ip */ - popf /* Pop flags at end (no addl to corrupt flags) */ - jmp .Lftrace_ret - popf - jmp ftrace_stub + /* use lea to not affect flags */ + lea 3*4(%esp), %esp /* Skip orig_ax, ip and cs */ + + jmp .Lftrace_ret #else /* ! CONFIG_DYNAMIC_FTRACE */ ENTRY(mcount) |