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x86/traps: Use pt_regs directly in fixup_bad_iret()

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commit 0aca53c6b522f8d6e2681ca875acbbe105f5fdcf upstream.

Always stash the address error_entry() is going to return to, in %r12
and get rid of the void *error_entry_ret; slot in struct bad_iret_stack
which was supposed to account for it and pt_regs pushed on the stack.

After this, both fixup_bad_iret() and sync_regs() can work on a struct
pt_regs pointer directly.

  [ bp: Rewrite commit message, touch ups. ]

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220503032107.680190-2-jiangshanlai@gmail.com
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lai Jiangshan
2022-04-21 22:10:48 +08:00
committed by Greg Kroah-Hartman
parent 760adb59f6
commit 01bc8bd64c
3 changed files with 12 additions and 14 deletions
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5
arch/x86/entry/entry_64.S
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@@ -1041,9 +1041,12 @@ SYM_CODE_START_LOCAL(error_entry)
* Pretend that the exception came from user mode: set up pt_regs
* as if we faulted immediately after IRET.
*/
mov %rsp, %rdi
popq %r12 /* save return addr in %12 */
movq %rsp, %rdi /* arg0 = pt_regs pointer */
call fixup_bad_iret
mov %rax, %rsp
ENCODE_FRAME_POINTER
pushq %r12
jmp .Lerror_entry_from_usermode_after_swapgs
SYM_CODE_END(error_entry)