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From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Laurent Dufour <ldufour@linux.ibm.com>,
	Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 07/14] powerpc/rtas: PACA can be restored directly from SPRG
Date: Tue,  8 Mar 2022 23:50:40 +1000	[thread overview]
Message-ID: <20220308135047.478297-8-npiggin@gmail.com> (raw)
In-Reply-To: <20220308135047.478297-1-npiggin@gmail.com>

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


  parent reply	other threads:[~2022-03-08 13:55 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-08 13:50 [PATCH 00/14] powerpc/rtas: various cleanups and improvements Nicholas Piggin
2022-03-08 13:50 ` [PATCH 01/14] powerpc/rtas: Move rtas entry assembly into its own file Nicholas Piggin
2022-03-08 13:50 ` [PATCH 02/14] powerpc/rtas: Make enter_rtas a nokprobe symbol on 64-bit Nicholas Piggin
2022-03-08 13:50 ` [PATCH 03/14] powerpc/rtas: Fix whitespace in rtas_entry.S Nicholas Piggin
2022-03-08 13:50 ` [PATCH 04/14] powerpc/rtas: Call enter_rtas with MSR[EE] disabled Nicholas Piggin
2022-03-14 15:12   ` Laurent Dufour
2022-03-08 13:50 ` [PATCH 05/14] powerpc/rtas: Modernise RI clearing on 64-bit Nicholas Piggin
2022-03-14 15:15   ` Laurent Dufour
2022-03-08 13:50 ` [PATCH 06/14] powerpc/rtas: Load rtas entry MSR explicitly Nicholas Piggin
2022-03-14 15:17   ` Laurent Dufour
2022-03-08 13:50 ` Nicholas Piggin [this message]
2022-03-14 15:32   ` [PATCH 07/14] powerpc/rtas: PACA can be restored directly from SPRG Laurent Dufour
2022-03-08 13:50 ` [PATCH 08/14] powerpc/rtas: call enter_rtas in real-mode on 64-bit Nicholas Piggin
2022-03-14 17:09   ` Laurent Dufour
2022-03-17  9:36   ` Laurent Dufour
2022-03-08 13:50 ` [PATCH 09/14] powerpc/rtas: Leave MSR[RI] enabled over RTAS call Nicholas Piggin
2022-03-14 17:17   ` Laurent Dufour
2022-03-08 13:50 ` [PATCH 10/14] powerpc/rtas: replace rtas_call_unlocked with raw_rtas_call Nicholas Piggin
2022-03-14 17:30   ` Laurent Dufour
2022-03-08 13:50 ` [PATCH 11/14] powerpc/rtas: tidy __fetch_rtas_last_error Nicholas Piggin
2022-03-08 13:50 ` [PATCH 12/14] powerpc/rtas: Close theoretical memory leak Nicholas Piggin
2022-03-15 17:17   ` Laurent Dufour
2022-03-08 13:50 ` [PATCH 13/14] powerpc/rtas: enture rtas_call is called with MMU enabled Nicholas Piggin
2022-03-15 17:18   ` Laurent Dufour
2022-03-08 13:50 ` [PATCH 14/14] powerpc/rtas: Consolidate and improve checking for rtas callers Nicholas Piggin
2022-03-15 17:26   ` Laurent Dufour
2022-03-08 14:51 ` [PATCH 00/14] powerpc/rtas: various cleanups and improvements Christophe Leroy
2022-03-17 11:15 ` Laurent Dufour
2022-05-24 11:08 ` Michael Ellerman

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