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| author | Nicholas Piggin <npiggin@gmail.com> | 2021-06-18 01:51:08 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-25 00:06:56 +1000 |
| commit | f23699c93becd746295aaa506537882a46a62219 (patch) | |
| tree | ea44289996524915c83e6876b39babbe6a640ff8 /arch/powerpc/kernel/exceptions-64e.S | |
| parent | 63e40806eea984f770c992120bbfd71b589ea580 (diff) | |
| download | lwn-f23699c93becd746295aaa506537882a46a62219.tar.gz lwn-f23699c93becd746295aaa506537882a46a62219.zip | |
powerpc/64: allow alternate return locations for soft-masked interrupts
The exception table fixup adjusts a failed page fault's interrupt return
location if it was taken at an address specified in the exception table,
to a corresponding fixup handler address.
Introduce a variation of that idea which adds a fixup table for NMIs and
soft-masked asynchronous interrupts. This will be used to protect
certain critical sections that are sensitive to being clobbered by
interrupts coming in (due to using the same SPRs and/or irq soft-mask
state).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210617155116.2167984-10-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kernel/exceptions-64e.S')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64e.S | 37 |
1 files changed, 35 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index b35c97c7082f..1b79f8a75298 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S @@ -901,6 +901,28 @@ kernel_dbg_exc: bl unknown_exception b interrupt_return +.macro SEARCH_RESTART_TABLE + LOAD_REG_IMMEDIATE_SYM(r14, r11, __start___restart_table) + LOAD_REG_IMMEDIATE_SYM(r15, r11, __stop___restart_table) +300: + cmpd r14,r15 + beq 302f + ld r11,0(r14) + cmpld r10,r11 + blt 301f + ld r11,8(r14) + cmpld r10,r11 + bge 301f + ld r11,16(r14) + b 303f +301: + addi r14,r14,24 + b 300b +302: + li r11,0 +303: +.endm + /* * An interrupt came in while soft-disabled; We mark paca->irq_happened * accordingly and if the interrupt is level sensitive, we hard disable @@ -909,6 +931,9 @@ kernel_dbg_exc: */ .macro masked_interrupt_book3e paca_irq full_mask + std r14,PACA_EXGEN+EX_R14(r13) + std r15,PACA_EXGEN+EX_R15(r13) + lbz r10,PACAIRQHAPPENED(r13) .if \full_mask == 1 ori r10,r10,\paca_irq | PACA_IRQ_HARD_DIS @@ -918,15 +943,23 @@ kernel_dbg_exc: stb r10,PACAIRQHAPPENED(r13) .if \full_mask == 1 - rldicl r10,r11,48,1 /* clear MSR_EE */ - rotldi r11,r10,16 + xori r11,r11,MSR_EE /* clear MSR_EE */ mtspr SPRN_SRR1,r11 .endif + mfspr r10,SPRN_SRR0 + SEARCH_RESTART_TABLE + cmpdi r11,0 + beq 1f + mtspr SPRN_SRR0,r11 /* return to restart address */ +1: + lwz r11,PACA_EXGEN+EX_CR(r13) mtcr r11 ld r10,PACA_EXGEN+EX_R10(r13) ld r11,PACA_EXGEN+EX_R11(r13) + ld r14,PACA_EXGEN+EX_R14(r13) + ld r15,PACA_EXGEN+EX_R15(r13) mfspr r13,SPRN_SPRG_GEN_SCRATCH rfi b . |