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| author | Jan Beulich <JBeulich@suse.com> | 2011-09-28 16:57:52 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-09-28 19:04:52 +0200 |
| commit | eab9e6137f237681a04649e786cc4d942bedd6d1 (patch) | |
| tree | 8ab92f349f7bc33a9b0f1e93cd81ac0609157389 /arch/x86/kernel | |
| parent | e05139f2569ecf699b229a6473a86cdffed62956 (diff) | |
| download | lwn-eab9e6137f237681a04649e786cc4d942bedd6d1.tar.gz lwn-eab9e6137f237681a04649e786cc4d942bedd6d1.zip | |
x86-64: Fix CFI data for interrupt frames
The patch titled "x86: Don't use frame pointer to save old stack
on irq entry" did not properly adjust CFI directives, so this
patch is a follow-up to that one.
With the old stack pointer no longer stored in a callee-saved
register (plus some offset), we now have to use a CFA expression
to describe the memory location where it is being found. This
requires the use of .cfi_escape (allowing arbitrary byte streams
to be emitted into .eh_frame), as there is no
.cfi_def_cfa_expression (which also cannot reasonably be
expected, as it would require a full expression parser).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/4E8360200200007800058467@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 6419bb05ecd5..faf8d5e74b0b 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -331,10 +331,15 @@ ENDPROC(native_usergs_sysret64) 1: incl PER_CPU_VAR(irq_count) jne 2f mov PER_CPU_VAR(irq_stack_ptr),%rsp - EMPTY_FRAME 0 + CFI_DEF_CFA_REGISTER rsi 2: /* Store previous stack value */ pushq %rsi + CFI_ESCAPE 0x0f /* DW_CFA_def_cfa_expression */, 6, \ + 0x77 /* DW_OP_breg7 */, 0, \ + 0x06 /* DW_OP_deref */, \ + 0x08 /* DW_OP_const1u */, SS+8-RBP, \ + 0x22 /* DW_OP_plus */ /* We entered an interrupt context - irqs are off: */ TRACE_IRQS_OFF .endm @@ -788,7 +793,6 @@ END(interrupt) subq $ORIG_RAX-RBP, %rsp CFI_ADJUST_CFA_OFFSET ORIG_RAX-RBP SAVE_ARGS_IRQ - PARTIAL_FRAME 0 call \func .endm @@ -813,10 +817,10 @@ ret_from_intr: /* Restore saved previous stack */ popq %rsi - leaq 16(%rsi), %rsp - + CFI_DEF_CFA_REGISTER rsi + leaq ARGOFFSET-RBP(%rsi), %rsp CFI_DEF_CFA_REGISTER rsp - CFI_ADJUST_CFA_OFFSET -16 + CFI_ADJUST_CFA_OFFSET RBP-ARGOFFSET exit_intr: GET_THREAD_INFO(%rcx) |