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7e1864332f
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: 31da94c25a ("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>
72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2015 Regents of the University of California
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*/
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#ifndef _ASM_RISCV_ASM_H
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#define _ASM_RISCV_ASM_H
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#ifdef __ASSEMBLY__
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#define __ASM_STR(x) x
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#else
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#define __ASM_STR(x) #x
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#endif
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#if __riscv_xlen == 64
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#define __REG_SEL(a, b) __ASM_STR(a)
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#elif __riscv_xlen == 32
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#define __REG_SEL(a, b) __ASM_STR(b)
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#else
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#error "Unexpected __riscv_xlen"
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#endif
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#define REG_L __REG_SEL(ld, lw)
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#define REG_S __REG_SEL(sd, sw)
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#define REG_SC __REG_SEL(sc.d, sc.w)
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#define REG_AMOSWAP_AQ __REG_SEL(amoswap.d.aq, amoswap.w.aq)
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#define REG_ASM __REG_SEL(.dword, .word)
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#define SZREG __REG_SEL(8, 4)
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#define LGREG __REG_SEL(3, 2)
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#if __SIZEOF_POINTER__ == 8
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#ifdef __ASSEMBLY__
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#define RISCV_PTR .dword
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#define RISCV_SZPTR 8
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#define RISCV_LGPTR 3
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#else
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#define RISCV_PTR ".dword"
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#define RISCV_SZPTR "8"
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#define RISCV_LGPTR "3"
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#endif
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#elif __SIZEOF_POINTER__ == 4
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#ifdef __ASSEMBLY__
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#define RISCV_PTR .word
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#define RISCV_SZPTR 4
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#define RISCV_LGPTR 2
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#else
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#define RISCV_PTR ".word"
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#define RISCV_SZPTR "4"
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#define RISCV_LGPTR "2"
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#endif
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#else
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#error "Unexpected __SIZEOF_POINTER__"
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#endif
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#if (__SIZEOF_INT__ == 4)
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#define RISCV_INT __ASM_STR(.word)
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#define RISCV_SZINT __ASM_STR(4)
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#define RISCV_LGINT __ASM_STR(2)
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#else
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#error "Unexpected __SIZEOF_INT__"
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#endif
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#if (__SIZEOF_SHORT__ == 2)
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#define RISCV_SHORT __ASM_STR(.half)
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#define RISCV_SZSHORT __ASM_STR(2)
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#define RISCV_LGSHORT __ASM_STR(1)
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#else
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#error "Unexpected __SIZEOF_SHORT__"
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#endif
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#endif /* _ASM_RISCV_ASM_H */
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