From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: <linuxppc-dev@ozlabs.org>
Subject: [PATCH 2/20] powerpc/of: Remove useless register save/restore when calling OF back
Date: Thu, 23 Jul 2009 15:59:38 +1000 [thread overview]
Message-ID: <20090723055949.F1844DDD1B@ozlabs.org> (raw)
enter_prom() used to save and restore registers such as CTR, XER etc..
which are volatile, or SRR0,1... which we don't care about. This
removes a bunch of useless code and while at it turns an mtmsrd into
an MTMSRD macro which will be useful to Book3E.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/kernel/entry_64.S | 38 ++++++--------------------------------
1 file changed, 6 insertions(+), 32 deletions(-)
--- linux-work.orig/arch/powerpc/kernel/entry_64.S 2009-07-22 15:20:26.000000000 +1000
+++ linux-work/arch/powerpc/kernel/entry_64.S 2009-07-22 15:22:44.000000000 +1000
@@ -823,30 +823,17 @@ _GLOBAL(enter_prom)
* of all registers that it saves. We therefore save those registers
* PROM might touch to the stack. (r0, r3-r13 are caller saved)
*/
- SAVE_8GPRS(2, r1)
+ SAVE_GPR(2, r1)
SAVE_GPR(13, r1)
SAVE_8GPRS(14, r1)
SAVE_10GPRS(22, r1)
- mfcr r4
- std r4,_CCR(r1)
- mfctr r5
- std r5,_CTR(r1)
- mfspr r6,SPRN_XER
- std r6,_XER(r1)
- mfdar r7
- std r7,_DAR(r1)
- mfdsisr r8
- std r8,_DSISR(r1)
- mfsrr0 r9
- std r9,_SRR0(r1)
- mfsrr1 r10
- std r10,_SRR1(r1)
+ mfcr r10
mfmsr r11
+ std r10,_CCR(r1)
std r11,_MSR(r1)
/* Get the PROM entrypoint */
- ld r0,GPR4(r1)
- mtlr r0
+ mtlr r4
/* Switch MSR to 32 bits mode
*/
@@ -860,8 +847,7 @@ _GLOBAL(enter_prom)
mtmsrd r11
isync
- /* Restore arguments & enter PROM here... */
- ld r3,GPR3(r1)
+ /* Enter PROM here... */
blrl
/* Just make sure that r1 top 32 bits didn't get
@@ -871,7 +857,7 @@ _GLOBAL(enter_prom)
/* Restore the MSR (back to 64 bits) */
ld r0,_MSR(r1)
- mtmsrd r0
+ MTMSRD(r0)
isync
/* Restore other registers */
@@ -881,18 +867,6 @@ _GLOBAL(enter_prom)
REST_10GPRS(22, r1)
ld r4,_CCR(r1)
mtcr r4
- ld r5,_CTR(r1)
- mtctr r5
- ld r6,_XER(r1)
- mtspr SPRN_XER,r6
- ld r7,_DAR(r1)
- mtdar r7
- ld r8,_DSISR(r1)
- mtdsisr r8
- ld r9,_SRR0(r1)
- mtsrr0 r9
- ld r10,_SRR1(r1)
- mtsrr1 r10
addi r1,r1,PROM_FRAME_SIZE
ld r0,16(r1)
next reply other threads:[~2009-07-23 5:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-23 5:59 Benjamin Herrenschmidt [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-07-24 9:15 [PATCH 0/20] powerpc: base 64-bit Book3E processor support (v2) Benjamin Herrenschmidt
2009-07-24 9:15 ` [PATCH 2/20] powerpc/of: Remove useless register save/restore when calling OF back Benjamin Herrenschmidt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20090723055949.F1844DDD1B@ozlabs.org \
--to=benh@kernel.crashing.org \
--cc=linuxppc-dev@ozlabs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).