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| author |   Nicholas Piggin <npiggin@gmail.com> | 2021-06-18 01:51:11 +1000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2021-06-25 00:06:56 +1000 |
| commit | 13799748b957bc5659f97c036224b0f4b42172e2 (patch) | |
| tree | 9d2cdb3ef6a336041e17e20c3d9aa55dd128ada8 /arch/powerpc/include/asm/paca.h | |
| parent | powerpc/64: treat low kernel text as irqs soft-masked (diff) | |
| download | linux-dev-13799748b957bc5659f97c036224b0f4b42172e2.tar.xz linux-dev-13799748b957bc5659f97c036224b0f4b42172e2.zip | |
powerpc/64: use interrupt restart table to speed up return from interrupt
Use the restart table facility to return from interrupt or system calls
without disabling MSR[EE] or MSR[RI].
Interrupt return asm is put into the low soft-masked region, to prevent
interrupts being processed here, although they are still taken as masked
interrupts which causes SRRs to be clobbered, and a pending soft-masked
interrupt to require replaying.
The return code uses restart table regions to redirct to a fixup handler
rather than continue with the exit, if such an interrupt happens. In
this case the interrupt return is redirected to a fixup handler which
reloads r1 for the interrupt stack and reloads registers and sets state
up to replay the soft-masked interrupt and try the exit again.
Some types of security exit fallback flushes and barriers are currently
unable to cope with reentrant interrupts, e.g., because they store some
state in the scratch SPR which would be clobbered even by masked
interrupts. For now the interrupts-enabled exits are disabled when these
flushes are used.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Guard unused exit_must_hard_disable() as reported by lkp]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210617155116.2167984-13-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/include/asm/paca.h')
| -rw-r--r-- | arch/powerpc/include/asm/paca.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index f5f0f3408047..dc05a862e72a 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -165,6 +165,9 @@ struct paca_struct { u64 kstack; /* Saved Kernel stack addr */ u64 saved_r1; /* r1 save for RTAS calls or PM or EE=0 */ u64 saved_msr; /* MSR saved here by enter_rtas */ +#ifdef CONFIG_PPC64 + u64 exit_save_r1; /* Syscall/interrupt R1 save */ +#endif #ifdef CONFIG_PPC_BOOK3E u16 trap_save; /* Used when bad stack is encountered */ #endif |