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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-10-26 08:39:25 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-11-18 21:16:57 +0300 |
| commit | 5a85790059385a051f1f647af37e8bac21674e61 (patch) | |
| tree | 0c9fee5e0d69e3257b23abfae3779b03bb71479d /arch/powerpc/mm | |
| parent | f7482771395535e1d216d0ad0891f4caed01d989 (diff) | |
| download | linux-5a85790059385a051f1f647af37e8bac21674e61.tar.xz | |
powerpc/book3e: Fix set_memory_x() and set_memory_nx()
[ 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.1635226743.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/nohash/tlb_low_64e.S | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/powerpc/mm/nohash/tlb_low_64e.S b/arch/powerpc/mm/nohash/tlb_low_64e.S index bf24451f3e71..9235e720e357 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) |