[PATCH] powerpc: Avoid bad relocations in iSeries code
Paul Mackerras
paulus at samba.org
Fri May 7 15:46:50 EST 2010
Subrata Modak reported that building a CONFIG_RELOCATABLE kernel with
CONFIG_ISERIES enabled gives the following warnings:
WARNING: 4 bad relocations
c00000000007216e R_PPC64_ADDR16_HIGHEST __ksymtab+0x00000000009dcec8
c000000000072172 R_PPC64_ADDR16_HIGHER __ksymtab+0x00000000009dcec8
c00000000007217a R_PPC64_ADDR16_HI __ksymtab+0x00000000009dcec8
c00000000007217e R_PPC64_ADDR16_LO __ksymtab+0x00000000009dcec8
The reason is that decrementer_iSeries_masked is using
LOAD_REG_IMMEDIATE to get the address of a kernel symbol, which
creates relocations that aren't handled by the kernel relocator code.
Instead of reading the tb_ticks_per_jiffy variable, we can just set
the decrementer to its maximum value (0x7fffffff) and that will work
just as well. In fact timer_interrupt sets the decrementer to that
value initially anyway, and we are sure to get into timer_interrupt
once interrupts are reenabled because we store 1 to the decrementer
interrupt flag in the lppaca (LPPACADECRINT(r12) here).
Reported-by: Subrata Modak <subrata at linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus at samba.org>
---
arch/powerpc/platforms/iseries/exception.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/iseries/exception.S b/arch/powerpc/platforms/iseries/exception.S
index fba5bf9..32a56c6 100644
--- a/arch/powerpc/platforms/iseries/exception.S
+++ b/arch/powerpc/platforms/iseries/exception.S
@@ -252,8 +252,8 @@ decrementer_iSeries_masked:
li r11,1
ld r12,PACALPPACAPTR(r13)
stb r11,LPPACADECRINT(r12)
- LOAD_REG_IMMEDIATE(r12, tb_ticks_per_jiffy)
- lwz r12,0(r12)
+ li r12,-1
+ clrldi r12,r12,33 /* set DEC to 0x7fffffff */
mtspr SPRN_DEC,r12
/* fall through */
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