diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2021-01-11 07:24:08 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-01-20 05:58:19 +0100 |
| commit | 08685be7761d69914f08c3d6211c543a385a5b9c (patch) | |
| tree | 4ca6766ab8b6d80777e668ffa7c1e9fc51e2d2df /arch/powerpc/kernel | |
| parent | selftests/powerpc: Only test lwm/stmw on big endian (diff) | |
| download | linux-08685be7761d69914f08c3d6211c543a385a5b9c.tar.xz linux-08685be7761d69914f08c3d6211c543a385a5b9c.zip | |
powerpc/64s: fix scv entry fallback flush vs interrupt
The L1D flush fallback functions are not recoverable vs interrupts,
yet the scv entry flush runs with MSR[EE]=1. This can result in a
timer (soft-NMI) or MCE or SRESET interrupt hitting here and overwriting
the EXRFI save area, which ends up corrupting userspace registers for
scv return.
Fix this by disabling RI and EE for the scv entry fallback flush.
Fixes: f79643787e0a0 ("powerpc/64s: flush L1D on kernel entry")
Cc: stable@vger.kernel.org # 5.9+ which also have flush L1D patch backport
Reported-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210111062408.287092-1-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 2 | ||||
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 19 | ||||
| -rw-r--r-- | arch/powerpc/kernel/vmlinux.lds.S | 7 |
3 files changed, 27 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index aa1af139d947..33ddfeef4fe9 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -75,7 +75,7 @@ BEGIN_FTR_SECTION bne .Ltabort_syscall END_FTR_SECTION_IFSET(CPU_FTR_TM) #endif - INTERRUPT_TO_KERNEL + SCV_INTERRUPT_TO_KERNEL mr r10,r1 ld r1,PACAKSAVE(r13) std r10,0(r1) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index e02ad6fefa46..6e53f7638737 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -2993,6 +2993,25 @@ TRAMP_REAL_BEGIN(entry_flush_fallback) ld r11,PACA_EXRFI+EX_R11(r13) blr +/* + * The SCV entry flush happens with interrupts enabled, so it must disable + * to prevent EXRFI being clobbered by NMIs (e.g., soft_nmi_common). r10 + * (containing LR) does not need to be preserved here because scv entry + * puts 0 in the pt_regs, CTR can be clobbered for the same reason. + */ +TRAMP_REAL_BEGIN(scv_entry_flush_fallback) + li r10,0 + mtmsrd r10,1 + lbz r10,PACAIRQHAPPENED(r13) + ori r10,r10,PACA_IRQ_HARD_DIS + stb r10,PACAIRQHAPPENED(r13) + std r11,PACA_EXRFI+EX_R11(r13) + L1D_DISPLACEMENT_FLUSH + ld r11,PACA_EXRFI+EX_R11(r13) + li r10,MSR_RI + mtmsrd r10,1 + blr + TRAMP_REAL_BEGIN(rfi_flush_fallback) SET_SCRATCH0(r13); GET_PACA(r13); diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 4ab426b8b0e0..72fa3c00229a 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -146,6 +146,13 @@ SECTIONS } . = ALIGN(8); + __scv_entry_flush_fixup : AT(ADDR(__scv_entry_flush_fixup) - LOAD_OFFSET) { + __start___scv_entry_flush_fixup = .; + *(__scv_entry_flush_fixup) + __stop___scv_entry_flush_fixup = .; + } + + . = ALIGN(8); __stf_exit_barrier_fixup : AT(ADDR(__stf_exit_barrier_fixup) - LOAD_OFFSET) { __start___stf_exit_barrier_fixup = .; *(__stf_exit_barrier_fixup) |