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| author | Peter Zijlstra <peterz@infradead.org> | 2019-05-07 23:25:54 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-06-25 10:23:47 +0200 |
| commit | 3c88c692c28746473791276f8b42d2c989d6cbe6 (patch) | |
| tree | 51cb03ef4cbb611f42ea43c8737be894991b656b /arch/x86/kernel/kprobes/opt.c | |
| parent | ea1ed38dba64b64a245ab8ca1406269d17b99485 (diff) | |
| download | linux-3c88c692c28746473791276f8b42d2c989d6cbe6.tar.bz2 | |
x86/stackframe/32: Provide consistent pt_regs
Currently pt_regs on x86_32 has an oddity in that kernel regs
(!user_mode(regs)) are short two entries (esp/ss). This means that any
code trying to use them (typically: regs->sp) needs to jump through
some unfortunate hoops.
Change the entry code to fix this up and create a full pt_regs frame.
This then simplifies various trampolines in ftrace and kprobes, the
stack unwinder, ptrace, kdump and kgdb.
Much thanks to Josh for help with the cleanups!
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/kprobes/opt.c')
| -rw-r--r-- | arch/x86/kernel/kprobes/opt.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 7c361a24c6df..282b4eb67e30 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -102,14 +102,15 @@ asm ( "optprobe_template_call:\n" ASM_NOP5 /* Move flags to rsp */ - " movq 144(%rsp), %rdx\n" - " movq %rdx, 152(%rsp)\n" + " movq 18*8(%rsp), %rdx\n" + " movq %rdx, 19*8(%rsp)\n" RESTORE_REGS_STRING /* Skip flags entry */ " addq $8, %rsp\n" " popfq\n" #else /* CONFIG_X86_32 */ - " pushf\n" + " pushl %esp\n" + " pushfl\n" SAVE_REGS_STRING " movl %esp, %edx\n" ".global optprobe_template_val\n" @@ -118,9 +119,13 @@ asm ( ".global optprobe_template_call\n" "optprobe_template_call:\n" ASM_NOP5 + /* Move flags into esp */ + " movl 14*4(%esp), %edx\n" + " movl %edx, 15*4(%esp)\n" RESTORE_REGS_STRING - " addl $4, %esp\n" /* skip cs */ - " popf\n" + /* Skip flags entry */ + " addl $4, %esp\n" + " popfl\n" #endif ".global optprobe_template_end\n" "optprobe_template_end:\n" @@ -152,10 +157,9 @@ optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs) } else { struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); /* Save skipped registers */ -#ifdef CONFIG_X86_64 regs->cs = __KERNEL_CS; -#else - regs->cs = __KERNEL_CS | get_kernel_rpl(); +#ifdef CONFIG_X86_32 + regs->cs |= get_kernel_rpl(); regs->gs = 0; #endif regs->ip = (unsigned long)op->kp.addr + INT3_SIZE; |