[PATCH 07/14] powerpc/rtas: PACA can be restored directly from SPRG
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2022-03-08 13:55:58
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
On 64-bit, PACA is saved in a SPRG so it does not need to be saved on stack. We also don't need to mask off the top bits for real mode addresses because the architecture does this for us. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/kernel/rtas_entry.S | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/kernel/rtas_entry.S b/arch/powerpc/kernel/rtas_entry.S
index 08eb731f08b8..5f65ea4436c6 100644
--- a/arch/powerpc/kernel/rtas_entry.S
+++ b/arch/powerpc/kernel/rtas_entry.S@@ -62,10 +62,9 @@ _GLOBAL(enter_rtas) /* Because RTAS is running in 32b mode, it clobbers the high order half * of all registers that it saves. We therefore save those registers - * RTAS might touch to the stack. (r0, r3-r13 are caller saved) + * RTAS might touch to the stack. (r0, r3-r12 are caller saved) */ SAVE_GPR(2, r1) /* Save the TOC */ - SAVE_GPR(13, r1) /* Save paca */ SAVE_NVGPRS(r1) /* Save the non-volatiles */ mfcr r4
@@ -129,15 +128,14 @@ rtas_return_loc: mtmsrd r6 /* relocation is off at this point */ - GET_PACA(r4) - clrldi r4,r4,2 /* convert to realmode address */ + GET_PACA(r13) bcl 20,31,$+4 0: mflr r3 ld r3,(1f-0b)(r3) /* get &rtas_restore_regs */ - ld r1,PACAR1(r4) /* Restore our SP */ - ld r4,PACASAVEDMSR(r4) /* Restore our MSR */ + ld r1,PACAR1(r13) /* Restore our SP */ + ld r4,PACASAVEDMSR(r13) /* Restore our MSR */ mtspr SPRN_SRR0,r3 mtspr SPRN_SRR1,r4
@@ -153,11 +151,8 @@ _ASM_NOKPROBE_SYMBOL(rtas_return_loc) rtas_restore_regs: /* relocation is on at this point */ REST_GPR(2, r1) /* Restore the TOC */ - REST_GPR(13, r1) /* Restore paca */ REST_NVGPRS(r1) /* Restore the non-volatiles */ - GET_PACA(r13) - ld r4,_CCR(r1) mtcr r4 ld r5,_CTR(r1)
--
2.23.0