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authorMichael Ellerman <mpe@ellerman.id.au>2018-04-16 16:39:05 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2018-05-11 15:29:03 +0200
commit6158faed7c80256fb6b370781cb3cd6815f4ba69 (patch)
tree4ac69bbbda49b8975863df88893a370c0a7b8e0c
parentpowerpc/lib: Rename ftr_fixup_test7 to ftr_fixup_test_too_big (diff)
downloadlinux-6158faed7c80256fb6b370781cb3cd6815f4ba69.tar.xz
linux-6158faed7c80256fb6b370781cb3cd6815f4ba69.zip
powerpc/lib: Add alt patching test of branching past the last instruction
Add a test of the relative branch patching logic in the alternate section feature fixup code. This tests that if we branch past the last instruction of the alternate section, the branch is not patched. That's because the assembler will have created a branch that already points to the first instruction after the patched section, which is correct and needs no further patching. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/lib/feature-fixups-test.S36
-rw-r--r--arch/powerpc/lib/feature-fixups.c11
2 files changed, 47 insertions, 0 deletions
diff --git a/arch/powerpc/lib/feature-fixups-test.S b/arch/powerpc/lib/feature-fixups-test.S
index dd05afcbcde3..f16cec989506 100644
--- a/arch/powerpc/lib/feature-fixups-test.S
+++ b/arch/powerpc/lib/feature-fixups-test.S
@@ -171,6 +171,42 @@ globl(ftr_fixup_test6_expected)
or 2,2,2
or 3,3,3
+globl(ftr_fixup_test7)
+ or 1,1,1
+BEGIN_FTR_SECTION
+ or 2,2,2
+ or 2,2,2
+ or 2,2,2
+ or 2,2,2
+ or 2,2,2
+ or 2,2,2
+ or 2,2,2
+FTR_SECTION_ELSE
+2: b 3f
+3: or 5,5,5
+ beq 3b
+ b 1f
+ or 6,6,6
+ b 2b
+ bdnz 3b
+1:
+ALT_FTR_SECTION_END(0, 1)
+ or 1,1,1
+ or 1,1,1
+
+globl(end_ftr_fixup_test7)
+ nop
+
+globl(ftr_fixup_test7_expected)
+ or 1,1,1
+2: b 3f
+3: or 5,5,5
+ beq 3b
+ b 1f
+ or 6,6,6
+ b 2b
+ bdnz 3b
+1: or 1,1,1
#if 0
/* Test that if we have a larger else case the assembler spots it and
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index 097b45bd9de4..f3e46d4edd72 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -425,6 +425,16 @@ static void test_alternative_case_with_external_branch(void)
check(memcmp(ftr_fixup_test6, ftr_fixup_test6_expected, size) == 0);
}
+static void test_alternative_case_with_branch_to_end(void)
+{
+ extern unsigned int ftr_fixup_test7[];
+ extern unsigned int end_ftr_fixup_test7[];
+ extern unsigned int ftr_fixup_test7_expected[];
+ int size = 4 * (end_ftr_fixup_test7 - ftr_fixup_test7);
+
+ check(memcmp(ftr_fixup_test7, ftr_fixup_test7_expected, size) == 0);
+}
+
static void test_cpu_macros(void)
{
extern u8 ftr_fixup_test_FTR_macros[];
@@ -480,6 +490,7 @@ static int __init test_feature_fixups(void)
test_alternative_case_too_small();
test_alternative_case_with_branch();
test_alternative_case_with_external_branch();
+ test_alternative_case_with_branch_to_end();
test_cpu_macros();
test_fw_macros();
test_lwsync_macros();