Signed-off-by: Per Fransson per.xx.fransson@stericsson.com --- arch/arm/kernel/machine_kexec.c | 27 +++++++++++++++++++++- arch/arm/kernel/relocate_kernel.S | 23 +++++++++++++++++++ arch/arm/mm/mmu.c | 44 +++++++++++++++++++++++++++++++++++++ arch/arm/mm/proc-v7.S | 1 + 4 files changed, 94 insertions(+), 1 deletions(-)

diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index 3a8fd51..d5bb12f 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -17,12 +17,20 @@ extern const unsigned char relocate_new_kernel[]; extern const unsigned int relocate_new_kernel_size;

extern void setup_mm_for_reboot(char mode); +extern void identity_map(unsigned long, pgd_t*, pgd_t**);

extern unsigned long kexec_start_address; extern unsigned long kexec_indirection_page; extern unsigned long kexec_mach_type; extern unsigned long kexec_boot_atags;

+typedef struct { + pgd_t *ptr; + pgd_t store; +} kexec_mmu_ent_t; + +extern kexec_mmu_ent_t kexec_mmu_ents[4]; + /* * Provide a dummy crash_notes definition while crash dump arrives to arm. * This prevents breakage of crash_notes attribute in kernel/ksysfs.c. @@ -51,6 +59,7 @@ void machine_kexec(struct kimage *image) unsigned long reboot_code_buffer_phys; void *reboot_code_buffer;

+ unsigned long cpu_reset_phys;

page_list = image->head & PAGE_MASK;

@@ -65,18 +74,34 @@ void machine_kexec(struct kimage *image) kexec_mach_type = machine_arch_type; kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;

+ /* Identity map the code which turns off the mmu (cpu_reset) and + the code which will be executed immediately afterwards + (relocate_new_kernel). + Store the old entries so they can be restored. */ + /* cpu_reset cannot be used directly when MULTI_CPU is true, see + cpu-multi32.h, instead processor.reset will have to be used */ + cpu_reset_phys = virt_to_phys(cpu_reset); + identity_map(cpu_reset_phys, &kexec_mmu_ents[0].store, + &kexec_mmu_ents[0].ptr); + identity_map(((char *)cpu_reset_phys)+PGDIR_SIZE, + &kexec_mmu_ents[1].store, &kexec_mmu_ents[1].ptr); + identity_map(reboot_code_buffer_phys, + &kexec_mmu_ents[2].store, &kexec_mmu_ents[2].ptr); + identity_map(((char *)reboot_code_buffer_phys)+PGDIR_SIZE, + &kexec_mmu_ents[3].store, &kexec_mmu_ents[3].ptr); + /* copy our kernel relocation code to the control code page */ memcpy(reboot_code_buffer, relocate_new_kernel, relocate_new_kernel_size);

+ flush_icache_range((unsigned long) reboot_code_buffer, (unsigned long) reboot_code_buffer + KEXEC_CONTROL_PAGE_SIZE); printk(KERN_INFO "Bye!\n");

local_irq_disable(); local_fiq_disable(); - setup_mm_for_reboot(0); /* mode is not used, so just pass 0*/ flush_cache_all(); outer_flush_all(); outer_disable(); diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S index fd26f8d..36b1268 100644 --- a/arch/arm/kernel/relocate_kernel.S +++ b/arch/arm/kernel/relocate_kernel.S @@ -7,6 +7,23 @@ .globl relocate_new_kernel relocate_new_kernel:

+ /* We get here when the MMU is in a transitional state. + Wait for the virtual address mapping to wear off before + overwriting the identity mappings (set up for the sake + of MMU disabling) with the previous mappings. */ + ldr r0, =100 +0: subs r0, r0, #1 + beq 0b + + adr r0, kexec_mmu_ents + .rept 4 + ldr r1, [r0], #4 + ldr r2, [r0], #4 + str r2, [r1], #4 + ldr r2, [r0], #4 + str r2, [r1], #4 + .endr + ldr r0,kexec_indirection_page ldr r1,kexec_start_address

@@ -67,6 +84,12 @@ kexec_start_address: kexec_indirection_page: .long 0x0

+ + .globl kexec_mmu_ents +kexec_mmu_ents: + .space 4*12, 0 + + .globl kexec_mach_type kexec_mach_type: .long 0x0 diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index de3afc7..64f3f05 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -1080,3 +1080,47 @@ void setup_mm_for_reboot(char mode)

local_flush_tlb_all(); } + + +/* + * In order to soft-boot, we need to insert a 1:1 mapping in place of + * the user-mode pages. This will then ensure that we have predictable + * results when turning the mmu off + */ +void identity_map(unsigned long phys_addr, pmd_t *pmd_store, pmd_t **pmd_ptr) +{ + unsigned long base_pmdval; + pgd_t *pgd; + pmd_t *pmd; + int i; + unsigned long pmdval; + + /* + * We need to access to user-mode page tables here. For kernel threads + * we don't have any user-mode mappings so we use the context that we + * "borrowed". + */ + pgd = current->active_mm->pgd; + + base_pmdval = PMD_SECT_AP_WRITE | PMD_SECT_AP_READ | PMD_TYPE_SECT; + if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale()) + base_pmdval |= PMD_BIT4; + + /* Where to modify */ + pmd = pgd + (phys_addr >> PGDIR_SHIFT); + + /* Save old value */ + pmd_store[0] = pmd[0]; + pmd_store[1] = pmd[1]; + + *pmd_ptr = virt_to_phys(pmd); + + /* Set new value */ + pmdval = ((phys_addr >> PGDIR_SHIFT) << PGDIR_SHIFT) | base_pmdval; + pmd[0] = __pmd(pmdval); + pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1))); + + flush_pmd_entry(pmd); + local_flush_tlb_all(); +} + diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index b249143..37ee55b 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -61,6 +61,7 @@ ENDPROC(cpu_v7_proc_fin) */ .align 5 ENTRY(cpu_v7_reset) + sub pc, pc, #PAGE_OFFSET+4 @ go to physical addresses mrc p15, 0, ip, c1, c0, 0 @ ctrl register bic ip, ip, #0x0001 @ ...............m mcr p15, 0, ip, c1, c0, 0 @ ctrl register