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SubjectRe: next-20170217 boot on POWER8 LPAR : WARNING @kernel/jump_label.c:287
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On 02/20/2017 10:05 PM, Sachin Sant wrote:
>
>> On 20-Feb-2017, at 8:27 PM, Jason Baron <jbaron@akamai.com
>> <mailto:jbaron@akamai.com>> wrote:
>>
>> Hi,
>>
>> On 02/19/2017 09:07 AM, Sachin Sant wrote:
>>> While booting next-20170217 on a POWER8 LPAR following
>>> warning is displayed.
>>>
>>> Reverting the following commit helps boot cleanly.
>>> commit 3821fd35b5 : jump_label: Reduce the size of struct static_key
>>>
>>> [ 11.393008] ------------[ cut here ]------------
>>> [ 11.393031] WARNING: CPU: 5 PID: 2890 at kernel/jump_label.c:287
>>> static_key_set_entries.isra.10+0x3c/0x50
>>
>> Thanks for the report. So this is saying that the jump_entry table is
>> not at least 4-byte aligned. I wonder if this fixes it up?
>>
>
> Yes. With this patch the warning is gone.
>

Hi,

Thanks for testing. We probably need something like the following to
make sure we don't hit this on other arches. Steve - I will send 4
separate patches for this to get arch maintainers' acks for this?

Thanks,

-Jason

diff --git a/arch/arm/include/asm/jump_label.h
b/arch/arm/include/asm/jump_label.h
index 34f7b6980d21..9720c2f1850b 100644
--- a/arch/arm/include/asm/jump_label.h
+++ b/arch/arm/include/asm/jump_label.h
@@ -13,6 +13,7 @@ static __always_inline bool arch_static_branch(struct
static_key *key, bool bran
asm_volatile_goto("1:\n\t"
WASM(nop) "\n\t"
".pushsection __jump_table, \"aw\"\n\t"
+ ".balign 4 \n\t"
".word 1b, %l[l_yes], %c0\n\t"
".popsection\n\t"
: : "i" (&((char *)key)[branch]) : : l_yes);
@@ -27,6 +28,7 @@ static __always_inline bool
arch_static_branch_jump(struct static_key *key, bool
asm_volatile_goto("1:\n\t"
WASM(b) " %l[l_yes]\n\t"
".pushsection __jump_table, \"aw\"\n\t"
+ ".balign 4 \n\t"
".word 1b, %l[l_yes], %c0\n\t"
".popsection\n\t"
: : "i" (&((char *)key)[branch]) : : l_yes);
diff --git a/arch/mips/include/asm/jump_label.h
b/arch/mips/include/asm/jump_label.h
index e77672539e8e..51ce97dda3cc 100644
--- a/arch/mips/include/asm/jump_label.h
+++ b/arch/mips/include/asm/jump_label.h
@@ -31,6 +31,7 @@ static __always_inline bool arch_static_branch(struct
static_key *key, bool bran
asm_volatile_goto("1:\t" NOP_INSN "\n\t"
"nop\n\t"
".pushsection __jump_table, \"aw\"\n\t"
+ ".balign 4 \n\t"
WORD_INSN " 1b, %l[l_yes], %0\n\t"
".popsection\n\t"
: : "i" (&((char *)key)[branch]) : : l_yes);
@@ -45,6 +46,7 @@ static __always_inline bool
arch_static_branch_jump(struct static_key *key, bool
asm_volatile_goto("1:\tj %l[l_yes]\n\t"
"nop\n\t"
".pushsection __jump_table, \"aw\"\n\t"
+ ".balign 4 \n\t"
WORD_INSN " 1b, %l[l_yes], %0\n\t"
".popsection\n\t"
: : "i" (&((char *)key)[branch]) : : l_yes);
diff --git a/arch/powerpc/include/asm/jump_label.h
b/arch/powerpc/include/asm/jump_label.h
index 9a287e0ac8b1..f870a85bac46 100644
--- a/arch/powerpc/include/asm/jump_label.h
+++ b/arch/powerpc/include/asm/jump_label.h
@@ -24,6 +24,7 @@ static __always_inline bool arch_static_branch(struct
static_key *key, bool bran
asm_volatile_goto("1:\n\t"
"nop # arch_static_branch\n\t"
".pushsection __jump_table, \"aw\"\n\t"
+ ".balign 4 \n\t"
JUMP_ENTRY_TYPE "1b, %l[l_yes], %c0\n\t"
".popsection \n\t"
: : "i" (&((char *)key)[branch]) : : l_yes);
@@ -38,6 +39,7 @@ static __always_inline bool
arch_static_branch_jump(struct static_key *key, bool
asm_volatile_goto("1:\n\t"
"b %l[l_yes] # arch_static_branch_jump\n\t"
".pushsection __jump_table, \"aw\"\n\t"
+ ".balign 4 \n\t"
JUMP_ENTRY_TYPE "1b, %l[l_yes], %c0\n\t"
".popsection \n\t"
: : "i" (&((char *)key)[branch]) : : l_yes);
@@ -63,6 +65,7 @@ struct jump_entry {
#define ARCH_STATIC_BRANCH(LABEL, KEY) \
1098: nop; \
.pushsection __jump_table, "aw"; \
+ .balign 4; \
FTR_ENTRY_LONG 1098b, LABEL, KEY; \
.popsection
#endif
diff --git a/arch/tile/include/asm/jump_label.h
b/arch/tile/include/asm/jump_label.h
index cde7573f397b..c9f6125c41ef 100644
--- a/arch/tile/include/asm/jump_label.h
+++ b/arch/tile/include/asm/jump_label.h
@@ -25,6 +25,7 @@ static __always_inline bool arch_static_branch(struct
static_key *key,
asm_volatile_goto("1:\n\t"
"nop" "\n\t"
".pushsection __jump_table, \"aw\"\n\t"
+ ".balign 4 \n\t"
".quad 1b, %l[l_yes], %0 + %1 \n\t"
".popsection\n\t"
: : "i" (key), "i" (branch) : : l_yes);
@@ -39,6 +40,7 @@ static __always_inline bool
arch_static_branch_jump(struct static_key *key,
asm_volatile_goto("1:\n\t"
"j %l[l_yes]" "\n\t"
".pushsection __jump_table, \"aw\"\n\t"
+ ".balign 4 \n\t"
".quad 1b, %l[l_yes], %0 + %1 \n\t"
".popsection\n\t"
: : "i" (key), "i" (branch) : : l_yes);
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