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| author |   Alexandre Chartre <alexandre.chartre@oracle.com> | 2022-07-13 21:58:08 +0200 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2022-07-14 09:45:12 +0200 |
| commit | d16e0b26672066035439b2f49887f6576c4a3689 (patch) | |
| tree | 344c305d091ecbfeb36d9612c59ad442d3d4847a | |
| parent | x86/bugs: Mark retbleed_strings static (diff) | |
| download | linux-dev-d16e0b26672066035439b2f49887f6576c4a3689.tar.xz linux-dev-d16e0b26672066035439b2f49887f6576c4a3689.zip | |
x86/entry: Remove UNTRAIN_RET from native_irq_return_ldt
UNTRAIN_RET is not needed in native_irq_return_ldt because RET
untraining has already been done at this point.
In addition, when the RETBleed mitigation is IBPB, UNTRAIN_RET clobbers
several registers (AX, CX, DX) so here it trashes user values which are
in these registers.
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/35b0d50f-12d1-10c3-f5e8-d6c140486d4a@oracle.com
| -rw-r--r-- | arch/x86/entry/entry_64.S | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 285e043a3e40..9953d966d124 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -727,7 +727,6 @@ native_irq_return_ldt: pushq %rdi /* Stash user RDI */ swapgs /* to kernel GS */ SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi /* to kernel CR3 */ - UNTRAIN_RET movq PER_CPU_VAR(espfix_waddr), %rdi movq %rax, (0*8)(%rdi) /* user RAX */ |