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authorNicholas Piggin <npiggin@gmail.com>2021-06-17 18:51:03 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2021-06-24 17:06:55 +0300
commit59dc5bfca0cb6a29db1a50847684eb5c19f8f400 (patch)
treee59ddd65cf780da3df22074afee961dc8503cdc2 /arch/powerpc/math-emu
parent1df7d5e4baeac74d14c1bee18b2dff9302b3efbc (diff)
downloadlinux-59dc5bfca0cb6a29db1a50847684eb5c19f8f400.tar.xz
powerpc/64s: avoid reloading (H)SRR registers if they are still valid
When an interrupt is taken, the SRR registers are set to return to where it left off. Unless they are modified in the meantime, or the return address or MSR are modified, there is no need to reload these registers when returning from interrupt. Introduce per-CPU flags that track the validity of SRR and HSRR registers. These are cleared when returning from interrupt, when using the registers for something else (e.g., OPAL calls), when adjusting the return address or MSR of a context, and when context switching (which changes the return address and MSR). This improves the performance of interrupt returns. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Fold in fixup patch from Nick] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/math-emu')
-rw-r--r--arch/powerpc/math-emu/math.c2
-rw-r--r--arch/powerpc/math-emu/math_efp.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/math-emu/math.c b/arch/powerpc/math-emu/math.c
index 327165f26ca6..36761bd00f38 100644
--- a/arch/powerpc/math-emu/math.c
+++ b/arch/powerpc/math-emu/math.c
@@ -453,7 +453,7 @@ do_mathemu(struct pt_regs *regs)
break;
}
- regs->nip += 4;
+ regs_add_return_ip(regs, 4);
return 0;
illegal:
diff --git a/arch/powerpc/math-emu/math_efp.c b/arch/powerpc/math-emu/math_efp.c
index 0a05e51964c1..39b84e7452e1 100644
--- a/arch/powerpc/math-emu/math_efp.c
+++ b/arch/powerpc/math-emu/math_efp.c
@@ -710,7 +710,7 @@ update_regs:
illegal:
if (have_e500_cpu_a005_erratum) {
/* according to e500 cpu a005 erratum, reissue efp inst */
- regs->nip -= 4;
+ regs_add_return_ip(regs, -4);
pr_debug("re-issue efp inst: %08lx\n", speinsn);
return 0;
}