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| author |  Xin Li <xin3.li@intel.com>
| 2023-12-05 02:50:18 -0800 |
|---|---|---|
| committer |  Borislav Petkov (AMD) <bp@alien8.de>
| 2024-01-31 22:03:04 +0100 |
| commit | 5105e7687ad3dffde77f6e4393b5530e83d672dc (patch) | |
| tree | bc3f17dae2474cf5e4b411b6e249e2c52ceef121 /arch/x86/entry | |
| parent | x86/fred: Let ret_from_fork_asm() jmp to asm_fred_exit_user when FRED is enabled (diff) | |
| download | linux-5105e7687ad3dffde77f6e4393b5530e83d672dc.tar.gz linux-5105e7687ad3dffde77f6e4393b5530e83d672dc.tar.bz2 linux-5105e7687ad3dffde77f6e4393b5530e83d672dc.zip | |
x86/fred: Fixup fault on ERETU by jumping to fred_entrypoint_user
If the stack frame contains an invalid user context (e.g. due to invalid SS,
a non-canonical RIP, etc.) the ERETU instruction will trap (#SS or #GP).
From a Linux point of view, this really should be considered a user space
failure, so use the standard fault fixup mechanism to intercept the fault,
fix up the exception frame, and redirect execution to fred_entrypoint_user.
The end result is that it appears just as if the hardware had taken the
exception immediately after completing the transition to user space.
Suggested-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Shan Kang <shan.kang@intel.com>
Link: https://lore.kernel.org/r/20231205105030.8698-30-xin3.li@intel.com
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/entry_64_fred.S | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/entry/entry_64_fred.S b/arch/x86/entry/entry_64_fred.S index 2271a1c690dc..7fe2722ad90c 100644 --- a/arch/x86/entry/entry_64_fred.S +++ b/arch/x86/entry/entry_64_fred.S @@ -3,6 +3,7 @@ * The actual FRED entry points. */ +#include <asm/asm.h> #include <asm/fred.h> #include "calling.h" @@ -34,7 +35,9 @@ SYM_CODE_START_NOALIGN(asm_fred_entrypoint_user) call fred_entry_from_user SYM_INNER_LABEL(asm_fred_exit_user, SYM_L_GLOBAL) FRED_EXIT - ERETU +1: ERETU + + _ASM_EXTABLE_TYPE(1b, asm_fred_entrypoint_user, EX_TYPE_ERETU) SYM_CODE_END(asm_fred_entrypoint_user) /* |