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| author | Jisheng Zhang <jszhang@kernel.org> | 2022-10-30 15:45:17 +0300 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2022-11-30 05:16:55 +0300 |
| commit | 7e1864332fbc1b993659eab7974da9fe8bf8c128 (patch) | |
| tree | 3c6cd7287a3463cb214208ffceb5b4f0210360b0 /arch/riscv/include/asm/asm.h | |
| parent | 31da94c25aea835ceac00575a9fd206c5a833fed (diff) | |
| download | linux-7e1864332fbc1b993659eab7974da9fe8bf8c128.tar.xz | |
riscv: fix race when vmap stack overflow
Currently, when detecting vmap stack overflow, riscv firstly switches
to the so called shadow stack, then use this shadow stack to call the
get_overflow_stack() to get the overflow stack. However, there's
a race here if two or more harts use the same shadow stack at the same
time.
To solve this race, we introduce spin_shadow_stack atomic var, which
will be swap between its own address and 0 in atomic way, when the
var is set, it means the shadow_stack is being used; when the var
is cleared, it means the shadow_stack isn't being used.
Fixes: 31da94c25aea ("riscv: add VMAP_STACK overflow detection")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Suggested-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20221030124517.2370-1-jszhang@kernel.org
[Palmer: Add AQ to the swap, and also some comments.]
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/include/asm/asm.h')
| -rw-r--r-- | arch/riscv/include/asm/asm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h index 618d7c5af1a2..e15a1c9f1cf8 100644 --- a/arch/riscv/include/asm/asm.h +++ b/arch/riscv/include/asm/asm.h @@ -23,6 +23,7 @@ #define REG_L __REG_SEL(ld, lw) #define REG_S __REG_SEL(sd, sw) #define REG_SC __REG_SEL(sc.d, sc.w) +#define REG_AMOSWAP_AQ __REG_SEL(amoswap.d.aq, amoswap.w.aq) #define REG_ASM __REG_SEL(.dword, .word) #define SZREG __REG_SEL(8, 4) #define LGREG __REG_SEL(3, 2) |