[PATCH v6 1/3] ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15
From: Uwe Kleine-König <hidden>
Date: 2012-08-03 10:10:12
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
This makes cr_alignment a constant 0 to break code that tries to modify the value as it's likely that it's built on wrong assumption when CONFIG_CPU_CP15 isn't defined. For code that is only reading the value 0 is more or less a fine value to report. Signed-off-by: Uwe Kleine-K?nig <redacted> Forwarded: id:1333573807-23709-1-git-send-email-u.kleine-koenig at pengutronix.de --- arch/arm/include/asm/cp15.h | 11 ++++++++++- arch/arm/kernel/head-common.S | 9 +++++++-- arch/arm/mm/alignment.c | 2 ++ arch/arm/mm/mmu.c | 17 +++++++++++++++++ 4 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/cp15.h b/arch/arm/include/asm/cp15.h
index 5ef4d80..d814435 100644
--- a/arch/arm/include/asm/cp15.h
+++ b/arch/arm/include/asm/cp15.h@@ -42,6 +42,8 @@ #define vectors_high() (0) #endif +#ifdef CONFIG_CPU_CP15 + extern unsigned long cr_no_alignment; /* defined in entry-armv.S */ extern unsigned long cr_alignment; /* defined in entry-armv.S */
@@ -82,6 +84,13 @@ static inline void set_copro_access(unsigned int val) isb(); } -#endif +#else /* ifdef CONFIG_CPU_CP15 */ + +#define cr_no_alignment UL(0) +#define cr_alignment UL(0) + +#endif /* ifdef CONFIG_CPU_CP15 / else */ + +#endif /* ifndef __ASSEMBLY__ */ #endif
diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
index 854bd22..2f560c5 100644
--- a/arch/arm/kernel/head-common.S
+++ b/arch/arm/kernel/head-common.S@@ -98,8 +98,9 @@ __mmap_switched: str r9, [r4] @ Save processor ID str r1, [r5] @ Save machine type str r2, [r6] @ Save atags pointer - bic r4, r0, #CR_A @ Clear 'A' bit - stmia r7, {r0, r4} @ Save control register values + cmp r7, #0 + bicne r4, r0, #CR_A @ Clear 'A' bit + stmneia r7, {r0, r4} @ Save control register values b start_kernel ENDPROC(__mmap_switched)
@@ -113,7 +114,11 @@ __mmap_switched_data: .long processor_id @ r4 .long __machine_arch_type @ r5 .long __atags_pointer @ r6 +#ifdef CONFIG_CPU_CP15 .long cr_alignment @ r7 +#else + .long 0 +#endif .long init_thread_union + THREAD_START_SP @ sp .size __mmap_switched_data, . - __mmap_switched_data
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
index 9107231..7df07d1 100644
--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c@@ -962,12 +962,14 @@ static int __init alignment_init(void) return -ENOMEM; #endif +#ifdef CONFIG_CPU_CP15 if (cpu_is_v6_unaligned()) { cr_alignment &= ~CR_A; cr_no_alignment &= ~CR_A; set_cr(cr_alignment); ai_usermode = safe_usermode(ai_usermode, false); } +#endif hook_fault_code(FAULT_CODE_ALIGNMENT, do_alignment, SIGBUS, BUS_ADRALN, "alignment exception");
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index cf4528d..7a390f2 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c@@ -96,6 +96,7 @@ static struct cachepolicy cache_policies[] __initdata = { } }; +#ifdef CONFIG_CPU_CP15 /* * These are useful for identifying cache coherency * problems by allowing the cache or the cache and
@@ -194,6 +195,22 @@ void adjust_cr(unsigned long mask, unsigned long set) } #endif +#else + +static int __init early_cachepolicy(char *p) +{ + pr_warning("cachepolicy kernel parameter not supported without cp15\n"); +} +early_param("cachepolicy", early_cachepolicy); + +static int __init noalign_setup(char *__unused) +{ + pr_warning("noalign kernel parameter not supported without cp15\n"); +} +__setup("noalign", noalign_setup); + +#endif + #define PROT_PTE_DEVICE L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_XN #define PROT_SECT_DEVICE PMD_TYPE_SECT|PMD_SECT_AP_WRITE
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1.7.10.4