diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-09-04 10:47:48 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-10-04 20:23:36 +0100 |
| commit | f00ec48fadf5e37e7889f14cff900aa70d18b644 (patch) | |
| tree | 421cbce97167a78532aa825624f380caade3c0d2 /arch/arm/mm/proc-v6.S | |
| parent | 067173526c3bbc2eaeefcf6b7b2a9d998b9e8042 (diff) | |
ARM: Allow SMP kernels to boot on UP systems
UP systems do not implement all the instructions that SMP systems have,
so in order to boot a SMP kernel on a UP system, we need to rewrite
parts of the kernel.
Do this using an 'alternatives' scheme, where the kernel code and data
is modified prior to initialization to replace the SMP instructions,
thereby rendering the problematical code ineffectual. We use the linker
to generate a list of 32-bit word locations and their replacement values,
and run through these replacements when we detect a UP system.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm/proc-v6.S')
| -rw-r--r-- | arch/arm/mm/proc-v6.S | 43 |
1 files changed, 28 insertions, 15 deletions
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S index 22aac851519..b95662dedb6 100644 --- a/arch/arm/mm/proc-v6.S +++ b/arch/arm/mm/proc-v6.S @@ -30,13 +30,10 @@ #define TTB_RGN_WT (2 << 3) #define TTB_RGN_WB (3 << 3) -#ifndef CONFIG_SMP -#define TTB_FLAGS TTB_RGN_WBWA -#define PMD_FLAGS PMD_SECT_WB -#else -#define TTB_FLAGS TTB_RGN_WBWA|TTB_S -#define PMD_FLAGS PMD_SECT_WBWA|PMD_SECT_S -#endif +#define TTB_FLAGS_UP TTB_RGN_WBWA +#define PMD_FLAGS_UP PMD_SECT_WB +#define TTB_FLAGS_SMP TTB_RGN_WBWA|TTB_S +#define PMD_FLAGS_SMP PMD_SECT_WBWA|PMD_SECT_S ENTRY(cpu_v6_proc_init) mov pc, lr @@ -97,7 +94,8 @@ ENTRY(cpu_v6_switch_mm) #ifdef CONFIG_MMU mov r2, #0 ldr r1, [r1, #MM_CONTEXT_ID] @ get mm->context.id - orr r0, r0, #TTB_FLAGS + ALT_SMP(orr r0, r0, #TTB_FLAGS_SMP) + ALT_UP(orr r0, r0, #TTB_FLAGS_UP) mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB mcr p15, 0, r2, c7, c10, 4 @ drain write buffer mcr p15, 0, r0, c2, c0, 0 @ set TTB 0 @@ -156,9 +154,11 @@ cpu_pj4_name: */ __v6_setup: #ifdef CONFIG_SMP - mrc p15, 0, r0, c1, c0, 1 @ Enable SMP/nAMP mode + ALT_SMP(mrc p15, 0, r0, c1, c0, 1) @ Enable SMP/nAMP mode + ALT_UP(nop) orr r0, r0, #0x20 - mcr p15, 0, r0, c1, c0, 1 + ALT_SMP(mcr p15, 0, r0, c1, c0, 1) + ALT_UP(nop) #endif mov r0, #0 @@ -169,7 +169,8 @@ __v6_setup: #ifdef CONFIG_MMU mcr p15, 0, r0, c8, c7, 0 @ invalidate I + D TLBs mcr p15, 0, r0, c2, c0, 2 @ TTB control register - orr r4, r4, #TTB_FLAGS + ALT_SMP(orr r4, r4, #TTB_FLAGS_SMP) + ALT_UP(orr r4, r4, #TTB_FLAGS_UP) mcr p15, 0, r4, c2, c0, 1 @ load TTB1 #endif /* CONFIG_MMU */ adr r5, v6_crval @@ -225,10 +226,16 @@ cpu_elf_name: __v6_proc_info: .long 0x0007b000 .long 0x0007f000 - .long PMD_TYPE_SECT | \ + ALT_SMP(.long \ + PMD_TYPE_SECT | \ + PMD_SECT_AP_WRITE | \ + PMD_SECT_AP_READ | \ + PMD_FLAGS_SMP) + ALT_UP(.long \ + PMD_TYPE_SECT | \ PMD_SECT_AP_WRITE | \ PMD_SECT_AP_READ | \ - PMD_FLAGS + PMD_FLAGS_UP) .long PMD_TYPE_SECT | \ PMD_SECT_XN | \ PMD_SECT_AP_WRITE | \ @@ -249,10 +256,16 @@ __v6_proc_info: __pj4_v6_proc_info: .long 0x560f5810 .long 0xff0ffff0 - .long PMD_TYPE_SECT | \ + ALT_SMP(.long \ + PMD_TYPE_SECT | \ + PMD_SECT_AP_WRITE | \ + PMD_SECT_AP_READ | \ + PMD_FLAGS_SMP) + ALT_UP(.long \ + PMD_TYPE_SECT | \ PMD_SECT_AP_WRITE | \ PMD_SECT_AP_READ | \ - PMD_FLAGS + PMD_FLAGS_UP) .long PMD_TYPE_SECT | \ PMD_SECT_XN | \ PMD_SECT_AP_WRITE | \ |