[PATCH 1/3] ARM : kdump : Add LPAE support

Liu Hua
2014-03-27T08:00:38Z

With CONFIG_LPAE=y, memory in 32-bit ARM systems can exceed
4G. So if we use kdump in such systems. The capture kernel
should parse 64-bit elf header(parse_crash_elf64_headers).

And this process can not pass because ARM linux does not
supply related check function.

This patch adds check functions related of elf64 header.

Signed-off-by: Liu Hua <sdu.liu@huawei.com>
To: Russell King <linux@arm.linux.org.uk>
Cc: Dan Aloni <alonid@stratoscale.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: <linux-kernel@vger.kernel.org>
Cc: <kexec@lists.infradead.org>
---
arch/arm/include/asm/elf.h | 5 ++++-
arch/arm/kernel/elf.c | 33 +++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h
index f4b46d3..6e02a6d 100644
--- a/arch/arm/include/asm/elf.h
+++ b/arch/arm/include/asm/elf.h
@@ -90,14 +90,17 @@ typedef struct user_fp elf_fpregset_t;
extern char elf_platform[];

struct elf32_hdr;
+struct elf64_hdr;

/*
* This is used to ensure we don't load something for the wrong architecture.
*/
extern int elf_check_arch(const struct elf32_hdr *);
+extern int elf_check_arch_64(const struct elf64_hdr *);
#define elf_check_arch elf_check_arch

-#define vmcore_elf64_check_arch(x) (0)
+#define vmcore_elf64_check_arch(x) (elf_check_arch_64(x) || \
+ vmcore_elf_check_arch_cross(x))

extern int arm_elf_read_implies_exec(const struct elf32_hdr *, int);
#define elf_read_implies_exec(ex,stk) arm_elf_read_implies_exec(&(ex), stk)
diff --git a/arch/arm/kernel/elf.c b/arch/arm/kernel/elf.c
index d0d1e83..452086a 100644
--- a/arch/arm/kernel/elf.c
+++ b/arch/arm/kernel/elf.c
@@ -38,6 +38,39 @@ int elf_check_arch(const struct elf32_hdr *x)
}
EXPORT_SYMBOL(elf_check_arch);

+int elf_check_arch_64(const struct elf64_hdr *x)
+{
+ unsigned int eflags;
+
+ /* Make sure it's an ARM executable */
+ if (x->e_machine != EM_ARM)
+ return 0;
+
+ /* Make sure the entry address is reasonable */
+ if (x->e_entry & 1) {
+ if (!(elf_hwcap & HWCAP_THUMB))
+ return 0;
+ } else if (x->e_entry & 3)
+ return 0;
+
+ eflags = x->e_flags;
+ if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
+ unsigned int flt_fmt;
+
+ /* APCS26 is only allowed if the CPU supports it */
+ if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT))
+ return 0;
+
+ flt_fmt = eflags & (EF_ARM_VFP_FLOAT | EF_ARM_SOFT_FLOAT);
+
+ /* VFP requires the supporting code */
+ if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP))
+ return 0;
+ }
+ return 1;
+}
+EXPORT_SYMBOL(elf_check_arch_64);
+
void elf_set_personality(const struct elf32_hdr *x)
{
unsigned int eflags = x->e_flags;