From: Christophe Leroy christophe.leroy@csgroup.eu
[ Upstream commit b6cb20fdc2735f8b2e082937066c33fe376c2ee2 ]
set_memory_x() calls pte_mkexec() which sets _PAGE_EXEC. set_memory_nx() calls pte_exprotec() which clears _PAGE_EXEC.
Book3e has 2 bits, UX and SX, which defines the exec rights resp. for user (PR=1) and for kernel (PR=0).
_PAGE_EXEC is defined as UX only.
An executable kernel page is set with either _PAGE_KERNEL_RWX or _PAGE_KERNEL_ROX, which both have SX set and UX cleared.
So set_memory_nx() call for an executable kernel page does nothing because UX is already cleared.
And set_memory_x() on a non-executable kernel page makes it executable for the user and keeps it non-executable for kernel.
Also, pte_exec() always returns 'false' on kernel pages, because it checks _PAGE_EXEC which doesn't include SX, so for instance the W+X check doesn't work.
To fix this: - change tlb_low_64e.S to use _PAGE_BAP_UX instead of _PAGE_USER - sets both UX and SX in _PAGE_EXEC so that pte_exec() returns true whenever one of the two bits is set and pte_exprotect() clears both bits. - Define a book3e specific version of pte_mkexec() which sets either SX or UX based on UR.
Fixes: 1f9ad21c3b38 ("powerpc/mm: Implement set_memory() routines") Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/c41100f9c144dc5b62e5a751b810190c6b5d42fd.163522674... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/include/asm/nohash/32/pgtable.h | 2 ++ arch/powerpc/include/asm/nohash/64/pgtable.h | 5 ----- arch/powerpc/include/asm/nohash/pte-book3e.h | 18 ++++++++++++++---- arch/powerpc/mm/nohash/tlb_low_64e.S | 8 ++++---- 4 files changed, 20 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h index ac0a5ff48c3ad..d6ba821a56ced 100644 --- a/arch/powerpc/include/asm/nohash/32/pgtable.h +++ b/arch/powerpc/include/asm/nohash/32/pgtable.h @@ -193,10 +193,12 @@ static inline pte_t pte_wrprotect(pte_t pte) } #endif
+#ifndef pte_mkexec static inline pte_t pte_mkexec(pte_t pte) { return __pte(pte_val(pte) | _PAGE_EXEC); } +#endif
#define pmd_none(pmd) (!pmd_val(pmd)) #define pmd_bad(pmd) (pmd_val(pmd) & _PMD_BAD) diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h index d081704b13fb9..9d2905a474103 100644 --- a/arch/powerpc/include/asm/nohash/64/pgtable.h +++ b/arch/powerpc/include/asm/nohash/64/pgtable.h @@ -118,11 +118,6 @@ static inline pte_t pte_wrprotect(pte_t pte) return __pte(pte_val(pte) & ~_PAGE_RW); }
-static inline pte_t pte_mkexec(pte_t pte) -{ - return __pte(pte_val(pte) | _PAGE_EXEC); -} - #define PMD_BAD_BITS (PTE_TABLE_SIZE-1) #define PUD_BAD_BITS (PMD_TABLE_SIZE-1)
diff --git a/arch/powerpc/include/asm/nohash/pte-book3e.h b/arch/powerpc/include/asm/nohash/pte-book3e.h index 813918f407653..f798640422c2d 100644 --- a/arch/powerpc/include/asm/nohash/pte-book3e.h +++ b/arch/powerpc/include/asm/nohash/pte-book3e.h @@ -48,7 +48,7 @@ #define _PAGE_WRITETHRU 0x800000 /* W: cache write-through */
/* "Higher level" linux bit combinations */ -#define _PAGE_EXEC _PAGE_BAP_UX /* .. and was cache cleaned */ +#define _PAGE_EXEC (_PAGE_BAP_SX | _PAGE_BAP_UX) /* .. and was cache cleaned */ #define _PAGE_RW (_PAGE_BAP_SW | _PAGE_BAP_UW) /* User write permission */ #define _PAGE_KERNEL_RW (_PAGE_BAP_SW | _PAGE_BAP_SR | _PAGE_DIRTY) #define _PAGE_KERNEL_RO (_PAGE_BAP_SR) @@ -93,11 +93,11 @@ /* Permission masks used to generate the __P and __S table */ #define PAGE_NONE __pgprot(_PAGE_BASE) #define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) -#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC) +#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_BAP_UX) #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) -#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) +#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_BAP_UX) #define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER) -#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) +#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_BAP_UX)
#ifndef __ASSEMBLY__ static inline pte_t pte_mkprivileged(pte_t pte) @@ -113,6 +113,16 @@ static inline pte_t pte_mkuser(pte_t pte) }
#define pte_mkuser pte_mkuser + +static inline pte_t pte_mkexec(pte_t pte) +{ + if (pte_val(pte) & _PAGE_BAP_UR) + return __pte((pte_val(pte) & ~_PAGE_BAP_SX) | _PAGE_BAP_UX); + else + return __pte((pte_val(pte) & ~_PAGE_BAP_UX) | _PAGE_BAP_SX); +} +#define pte_mkexec pte_mkexec + #endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */ diff --git a/arch/powerpc/mm/nohash/tlb_low_64e.S b/arch/powerpc/mm/nohash/tlb_low_64e.S index bf24451f3e71f..9235e720e3572 100644 --- a/arch/powerpc/mm/nohash/tlb_low_64e.S +++ b/arch/powerpc/mm/nohash/tlb_low_64e.S @@ -222,7 +222,7 @@ tlb_miss_kernel_bolted:
tlb_miss_fault_bolted: /* We need to check if it was an instruction miss */ - andi. r10,r11,_PAGE_EXEC|_PAGE_BAP_SX + andi. r10,r11,_PAGE_BAP_UX|_PAGE_BAP_SX bne itlb_miss_fault_bolted dtlb_miss_fault_bolted: tlb_epilog_bolted @@ -239,7 +239,7 @@ itlb_miss_fault_bolted: srdi r15,r16,60 /* get region */ bne- itlb_miss_fault_bolted
- li r11,_PAGE_PRESENT|_PAGE_EXEC /* Base perm */ + li r11,_PAGE_PRESENT|_PAGE_BAP_UX /* Base perm */
/* We do the user/kernel test for the PID here along with the RW test */ @@ -614,7 +614,7 @@ itlb_miss_fault_e6500:
/* We do the user/kernel test for the PID here along with the RW test */ - li r11,_PAGE_PRESENT|_PAGE_EXEC /* Base perm */ + li r11,_PAGE_PRESENT|_PAGE_BAP_UX /* Base perm */ oris r11,r11,_PAGE_ACCESSED@h
cmpldi cr0,r15,0 /* Check for user region */ @@ -734,7 +734,7 @@ normal_tlb_miss_done:
normal_tlb_miss_access_fault: /* We need to check if it was an instruction miss */ - andi. r10,r11,_PAGE_EXEC + andi. r10,r11,_PAGE_BAP_UX bne 1f ld r14,EX_TLB_DEAR(r12) ld r15,EX_TLB_ESR(r12)