machine_kexec() need to set rw permission in text and rodata sections to assign some variables (e.g. kexec_start_address). To do that at the end (after flushing pdm in memory, inv D-Cache, etc.) it needs to invalidate TLB [section] entries.
If during the TLB invalidation an interrupt occours, which might cause a context switch, there is the risk to inject invalid TLBs, with ro permissions. When trying to assign .text labels, this lead to the following issue: "Unable to handle kernel paging request at virtual address <valid_addr>" with FSR 0x80d. Signed-off-by: Giancarlo Ferrari <[email protected]> --- arch/arm/kernel/machine_kexec.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index 76300f3..bbe912d 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -176,6 +176,13 @@ void machine_kexec(struct kimage *image) reboot_code_buffer = page_address(image->control_code_page); + /* + * If below part is not atomic TLB entries might be corrupted after TLB + * invalidation, which leads to Data Abort in .text variable assignment + */ + raw_local_irq_disable(); + local_fiq_disable(); + /* Prepare parameters for reboot_code_buffer*/ set_kernel_text_rw(); kexec_start_address = image->start; @@ -183,6 +190,9 @@ void machine_kexec(struct kimage *image) kexec_mach_type = machine_arch_type; kexec_boot_atags = image->arch.kernel_r2; + local_fiq_enable(); + raw_local_irq_enable(); + /* copy our kernel relocation code to the control code page */ reboot_entry = fncpy(reboot_code_buffer, &relocate_new_kernel, -- 2.7.4
