[PATCH v10 07/27] riscv mm: manufacture shadow stack pte
From: Deepak Gupta <hidden>
Date: 2025-02-10 20:27:00
Also in:
linux-arch, linux-devicetree, linux-fsdevel, linux-kselftest, linux-mm, linux-riscv, lkml
Subsystem:
risc-v architecture, the rest · Maintainers:
Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds
This patch implements creating shadow stack pte (on riscv). Creating shadow stack PTE on riscv means that clearing RWX and then setting W=1. Signed-off-by: Deepak Gupta <redacted> Reviewed-by: Alexandre Ghiti <redacted> --- arch/riscv/include/asm/pgtable.h | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 8c528cd7347a..ede43185ffdf 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h@@ -421,6 +421,11 @@ static inline pte_t pte_mkwrite_novma(pte_t pte) return __pte(pte_val(pte) | _PAGE_WRITE); } +static inline pte_t pte_mkwrite_shstk(pte_t pte) +{ + return __pte((pte_val(pte) & ~(_PAGE_LEAF)) | _PAGE_WRITE); +} + /* static inline pte_t pte_mkexec(pte_t pte) */ static inline pte_t pte_mkdirty(pte_t pte)
@@ -749,6 +754,11 @@ static inline pmd_t pmd_mkwrite_novma(pmd_t pmd) return pte_pmd(pte_mkwrite_novma(pmd_pte(pmd))); } +static inline pmd_t pmd_mkwrite_shstk(pmd_t pte) +{ + return __pmd((pmd_val(pte) & ~(_PAGE_LEAF)) | _PAGE_WRITE); +} + static inline pmd_t pmd_wrprotect(pmd_t pmd) { return pte_pmd(pte_wrprotect(pmd_pte(pmd)));
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2.34.1