From 0d70262a2d60886da6fe5b1fc8bbcd76cbbc306d Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 19 Jul 2017 23:09:58 +0100 Subject: ARM: kexec: fix failure to boot crash kernel When kexec was converted to DTB, the dtb address was passed between machine_kexec_prepare() and machine_kexec() using a static variable. This is bad news if you load a crash kernel followed by a normal kernel or vice versa - the last loaded kernel overwrites the dtb address. This can result in kexec failures, as (eg) we try to boot the crash kernel with the last loaded dtb. For example, with: the crash kernel fails to find the dtb. Avoid this by defining a kimage architecture structure, and store the address to be passed in r2 there, which will either be the ATAGs or the dtb blob. Fixes: 4cabd1d9625c ("ARM: 7539/1: kexec: scan for dtb magic in segments") Fixes: 42d720d1731a ("ARM: kexec: Make .text R/W in machine_kexec") Reported-by: Keerthy Tested-by: Keerthy Signed-off-by: Russell King --- arch/arm/include/asm/kexec.h | 5 +++++ arch/arm/kernel/machine_kexec.c | 11 ++++++----- 2 files changed, 11 insertions(+), 5 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/include/asm/kexec.h b/arch/arm/include/asm/kexec.h index 1869af6bac5c..25021b798a1e 100644 --- a/arch/arm/include/asm/kexec.h +++ b/arch/arm/include/asm/kexec.h @@ -19,6 +19,11 @@ #ifndef __ASSEMBLY__ +#define ARCH_HAS_KIMAGE_ARCH +struct kimage_arch { + u32 kernel_r2; +}; + /** * crash_setup_regs() - save registers for the panic kernel * @newregs: registers are saved here diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index 15495887ca14..fe1419eeb932 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -30,7 +30,6 @@ extern unsigned long kexec_boot_atags; static atomic_t waiting_for_crash_ipi; -static unsigned long dt_mem; /* * Provide a dummy crash_notes definition while crash dump arrives to arm. * This prevents breakage of crash_notes attribute in kernel/ksysfs.c. @@ -42,6 +41,9 @@ int machine_kexec_prepare(struct kimage *image) __be32 header; int i, err; + image->arch.kernel_r2 = image->start - KEXEC_ARM_ZIMAGE_OFFSET + + KEXEC_ARM_ATAGS_OFFSET; + /* * Validate that if the current HW supports SMP, then the SW supports * and implements CPU hotplug for the current HW. If not, we won't be @@ -66,8 +68,8 @@ int machine_kexec_prepare(struct kimage *image) if (err) return err; - if (be32_to_cpu(header) == OF_DT_HEADER) - dt_mem = current_segment->mem; + if (header == cpu_to_be32(OF_DT_HEADER)) + image->arch.kernel_r2 = current_segment->mem; } return 0; } @@ -165,8 +167,7 @@ void machine_kexec(struct kimage *image) kexec_start_address = image->start; kexec_indirection_page = page_list; kexec_mach_type = machine_arch_type; - kexec_boot_atags = dt_mem ?: image->start - KEXEC_ARM_ZIMAGE_OFFSET - + KEXEC_ARM_ATAGS_OFFSET; + kexec_boot_atags = image->arch.kernel_r2; /* copy our kernel relocation code to the control code page */ reboot_entry = fncpy(reboot_code_buffer, -- cgit v1.2.3