ARM: 7897/1: kexec: Use the right ISA for relocate_new_kernel

Copying a function with memcpy() and then trying to execute the result isn't trivially portable to Thumb. This patch modifies the kexec soft restart code to copy its assembler trampoline relocate_new_kernel() using fncpy() instead, so that relocate_new_kernel can be in the same ISA as the rest of the kernel without problems. Signed-off-by: Dave Martin <[email protected]> Acked-by: Will Deacon <[email protected]> Reported-by: Taras Kondratiuk <[email protected]> Tested-by: Taras Kondratiuk <[email protected]> Signed-off-by: Russell King <[email protected]>
torvalds · Nov 30, 2013 · e2ccba4 · e2ccba4
1 parent 5091333
commit e2ccba4
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Showing 2 changed files with 16 additions and 9 deletions.
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
@@ -14,11 +14,12 @@
 #include <asm/pgalloc.h>
 #include <asm/mmu_context.h>
 #include <asm/cacheflush.h>
+#include <asm/fncpy.h>
 #include <asm/mach-types.h>
 #include <asm/smp_plat.h>
 #include <asm/system_misc.h>
 
-extern const unsigned char relocate_new_kernel[];
+extern void relocate_new_kernel(void);
 extern const unsigned int relocate_new_kernel_size;
 
 extern unsigned long kexec_start_address;
@@ -142,6 +143,8 @@ void machine_kexec(struct kimage *image)
 {
  unsigned long page_list;
  unsigned long reboot_code_buffer_phys;
+ unsigned long reboot_entry = (unsigned long)relocate_new_kernel;
+ unsigned long reboot_entry_phys;
  void *reboot_code_buffer;
 
  /*
@@ -168,16 +171,16 @@ void machine_kexec(struct kimage *image)
 
 
  /* copy our kernel relocation code to the control code page */
- memcpy(reboot_code_buffer,
- relocate_new_kernel, relocate_new_kernel_size);
+ reboot_entry = fncpy(reboot_code_buffer,
+ reboot_entry,
+ relocate_new_kernel_size);
+ reboot_entry_phys = (unsigned long)reboot_entry +
+ (reboot_code_buffer_phys - (unsigned long)reboot_code_buffer);
 
-
- flush_icache_range((unsigned long) reboot_code_buffer,
- (unsigned long) reboot_code_buffer + KEXEC_CONTROL_PAGE_SIZE);
  printk(KERN_INFO "Bye!\n");
 
  if (kexec_reinit)
  kexec_reinit();
 
- soft_restart(reboot_code_buffer_phys);
+ soft_restart(reboot_entry_phys);
 }
diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
@@ -2,10 +2,12 @@
  * relocate_kernel.S - put the kernel image in place to boot
  */
 
+#include <linux/linkage.h>
 #include <asm/kexec.h>
 
- .globl relocate_new_kernel
-relocate_new_kernel:
+ .align 3 /* not needed for this code, but keeps fncpy() happy */
+
+ENTRY(relocate_new_kernel)
 
  ldr r0,kexec_indirection_page
  ldr r1,kexec_start_address
@@ -79,6 +81,8 @@ kexec_mach_type:
 kexec_boot_atags:
  .long 0x0
 
+ENDPROC(relocate_new_kernel)
+
 relocate_new_kernel_end:
 
  .globl relocate_new_kernel_size