arm/174461: commit references a PR
dfilter service
dfilter at FreeBSD.ORG
Sun Jan 27 20:30:01 UTC 2013
The following reply was made to PR arm/174461; it has been noted by GNATS.
From: dfilter at FreeBSD.ORG (dfilter service)
To: bug-followup at FreeBSD.org
Cc:
Subject: Re: arm/174461: commit references a PR
Date: Sun, 27 Jan 2013 20:28:23 +0000 (UTC)
Author: ian
Date: Sun Jan 27 20:28:14 2013
New Revision: 246001
URL: http://svnweb.freebsd.org/changeset/base/246001
Log:
Fix off-by-one errors in low-level arm9 and arm10 cache maintenance routines.
In all the routines that loop through a range of virtual addresses, the loop
is controlled by subtracting the cache line size from the total length of the
request. After the subtract, a 'bpl' instruction was used, which branches if
the result of the subtraction is zero or greater, but we need to exit the
loop when the count hits zero. Thus, all the bpl instructions in those loops
have been changed to 'bhi' (branch if greater than zero).
In addition, the two routines that walk through the cache using set-and-index
were correct, but confusing. The loop control for those has been simplified,
just so that it's easier to see by examination that the code is correct.
Routines for other arm architectures and generations still have the bpl
instruction, but compensate for the off-by-one situation by decrementing
the count register by one before entering the loop.
PR: arm/174461
Approved by: cognet (mentor)
Modified:
head/sys/arm/arm/cpufunc_asm_arm10.S
head/sys/arm/arm/cpufunc_asm_arm9.S
Modified: head/sys/arm/arm/cpufunc_asm_arm10.S
==============================================================================
--- head/sys/arm/arm/cpufunc_asm_arm10.S Sun Jan 27 20:16:50 2013 (r246000)
+++ head/sys/arm/arm/cpufunc_asm_arm10.S Sun Jan 27 20:28:14 2013 (r246001)
@@ -87,7 +87,7 @@ ENTRY_NP(arm10_icache_sync_range)
mcr p15, 0, r0, c7, c10, 1 /* Clean D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm10_sync_next
+ bhi .Larm10_sync_next
mcr p15, 0, r0, c7, c10, 4 /* drain the write buffer */
bx lr
@@ -108,12 +108,10 @@ ENTRY_NP(arm10_icache_sync_all)
orr ip, s_max, i_max
.Lnext_index:
mcr p15, 0, ip, c7, c10, 2 /* Clean D cache SE with Set/Index */
- sub ip, ip, i_inc
- tst ip, i_max /* Index 0 is last one */
- bne .Lnext_index /* Next index */
- mcr p15, 0, ip, c7, c10, 2 /* Clean D cache SE with Set/Index */
+ subs ip, ip, i_inc
+ bhs .Lnext_index /* Next index */
subs s_max, s_max, s_inc
- bpl .Lnext_set /* Next set */
+ bhs .Lnext_set /* Next set */
mcr p15, 0, r0, c7, c10, 4 /* drain the write buffer */
bx lr
@@ -133,7 +131,7 @@ ENTRY(arm10_dcache_wb_range)
mcr p15, 0, r0, c7, c10, 1 /* Clean D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm10_wb_next
+ bhi .Larm10_wb_next
mcr p15, 0, r0, c7, c10, 4 /* drain the write buffer */
bx lr
@@ -150,7 +148,7 @@ ENTRY(arm10_dcache_wbinv_range)
mcr p15, 0, r0, c7, c14, 1 /* Purge D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm10_wbinv_next
+ bhi .Larm10_wbinv_next
mcr p15, 0, r0, c7, c10, 4 /* drain the write buffer */
bx lr
@@ -171,7 +169,7 @@ ENTRY(arm10_dcache_inv_range)
mcr p15, 0, r0, c7, c6, 1 /* Invalidate D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm10_inv_next
+ bhi .Larm10_inv_next
mcr p15, 0, r0, c7, c10, 4 /* drain the write buffer */
bx lr
@@ -189,7 +187,7 @@ ENTRY(arm10_idcache_wbinv_range)
mcr p15, 0, r0, c7, c14, 1 /* Purge D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm10_id_wbinv_next
+ bhi .Larm10_id_wbinv_next
mcr p15, 0, r0, c7, c10, 4 /* drain the write buffer */
bx lr
@@ -211,12 +209,10 @@ ENTRY(arm10_dcache_wbinv_all)
orr ip, s_max, i_max
.Lnext_index_inv:
mcr p15, 0, ip, c7, c14, 2 /* Purge D cache SE with Set/Index */
- sub ip, ip, i_inc
- tst ip, i_max /* Index 0 is last one */
- bne .Lnext_index_inv /* Next index */
- mcr p15, 0, ip, c7, c14, 2 /* Purge D cache SE with Set/Index */
+ subs ip, ip, i_inc
+ bhs .Lnext_index_inv /* Next index */
subs s_max, s_max, s_inc
- bpl .Lnext_set_inv /* Next set */
+ bhs .Lnext_set_inv /* Next set */
mcr p15, 0, r0, c7, c10, 4 /* drain the write buffer */
bx lr
Modified: head/sys/arm/arm/cpufunc_asm_arm9.S
==============================================================================
--- head/sys/arm/arm/cpufunc_asm_arm9.S Sun Jan 27 20:16:50 2013 (r246000)
+++ head/sys/arm/arm/cpufunc_asm_arm9.S Sun Jan 27 20:28:14 2013 (r246001)
@@ -81,7 +81,7 @@ ENTRY_NP(arm9_icache_sync_range)
mcr p15, 0, r0, c7, c10, 1 /* Clean D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm9_sync_next
+ bhi .Larm9_sync_next
mov pc, lr
ENTRY_NP(arm9_icache_sync_all)
@@ -101,12 +101,10 @@ ENTRY_NP(arm9_icache_sync_all)
orr ip, s_max, i_max
.Lnext_index:
mcr p15, 0, ip, c7, c10, 2 /* Clean D cache SE with Set/Index */
- sub ip, ip, i_inc
- tst ip, i_max /* Index 0 is last one */
- bne .Lnext_index /* Next index */
- mcr p15, 0, ip, c7, c10, 2 /* Clean D cache SE with Set/Index */
+ subs ip, ip, i_inc
+ bhs .Lnext_index /* Next index */
subs s_max, s_max, s_inc
- bpl .Lnext_set /* Next set */
+ bhs .Lnext_set /* Next set */
mov pc, lr
.Larm9_line_size:
@@ -125,7 +123,7 @@ ENTRY(arm9_dcache_wb_range)
mcr p15, 0, r0, c7, c10, 1 /* Clean D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm9_wb_next
+ bhi .Larm9_wb_next
mov pc, lr
ENTRY(arm9_dcache_wbinv_range)
@@ -141,7 +139,7 @@ ENTRY(arm9_dcache_wbinv_range)
mcr p15, 0, r0, c7, c14, 1 /* Purge D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm9_wbinv_next
+ bhi .Larm9_wbinv_next
mov pc, lr
/*
@@ -161,7 +159,7 @@ ENTRY(arm9_dcache_inv_range)
mcr p15, 0, r0, c7, c6, 1 /* Invalidate D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm9_inv_next
+ bhi .Larm9_inv_next
mov pc, lr
ENTRY(arm9_idcache_wbinv_range)
@@ -178,7 +176,7 @@ ENTRY(arm9_idcache_wbinv_range)
mcr p15, 0, r0, c7, c14, 1 /* Purge D cache SE with VA */
add r0, r0, ip
subs r1, r1, ip
- bpl .Larm9_id_wbinv_next
+ bhi .Larm9_id_wbinv_next
mov pc, lr
ENTRY_NP(arm9_idcache_wbinv_all)
@@ -199,12 +197,10 @@ ENTRY(arm9_dcache_wbinv_all)
orr ip, s_max, i_max
.Lnext_index_inv:
mcr p15, 0, ip, c7, c14, 2 /* Purge D cache SE with Set/Index */
- sub ip, ip, i_inc
- tst ip, i_max /* Index 0 is last one */
- bne .Lnext_index_inv /* Next index */
- mcr p15, 0, ip, c7, c14, 2 /* Purge D cache SE with Set/Index */
+ subs ip, ip, i_inc
+ bhs .Lnext_index_inv /* Next index */
subs s_max, s_max, s_inc
- bpl .Lnext_set_inv /* Next set */
+ bhs .Lnext_set_inv /* Next set */
mov pc, lr
.Larm9_cache_data:
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