As of gcc 5.2.1 for Thumb-1, it is not possible any
more to assign gd from C code, as gd is mapped to r9,
and r9 may now be saved in the prolog sequence, and
restored in the epilog sequence, of any C functions.
Therefore arch_setup_gd(), which is supposed to set
r9, may actually have no effect, causing U-Boot to
use a bad address to access GD.
Fix this by never calling arch_setup_gd() for ARM,
and instead setting r9 in arch/arm/lib/crt0.S, to
the value returned by board_init_f_alloc_reserve().
Signed-off-by: Albert ARIBAUD <albert.u.b...@aribaud.net>
---
Changes in v6:
- moved ARM r9 fix into its own patch
Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2: None
arch/arm/lib/crt0.S | 2 ++
common/init/board_init.c | 8 ++++----
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index 4f2a712..9c34f2c 100644
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -85,6 +85,8 @@ ENTRY(_main)
mov r0, sp
bl board_init_f_alloc_reserve
mov sp, r0
+ /* set up gd here, outside any C code */
+ mov r9, r0
bl board_init_f_init_reserve
mov r0, #0
diff --git a/common/init/board_init.c b/common/init/board_init.c
index e649e07..d98648e 100644
--- a/common/init/board_init.c
+++ b/common/init/board_init.c
@@ -21,13 +21,13 @@ DECLARE_GLOBAL_DATA_PTR;
#define _USE_MEMCPY
#endif
-/* Unfortunately x86 can't compile this code as gd cannot be assigned */
-#ifndef CONFIG_X86
+/* Unfortunately x86 or ARM can't compile this code as gd cannot be assigned */
+#if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
__weak void arch_setup_gd(struct global_data *gd_ptr)
{
gd = gd_ptr;
}
-#endif /* !CONFIG_X86 */
+#endif /* !CONFIG_X86 && !CONFIG_ARM */
/*
* Allocate reserved space for use as 'globals' from 'top' address and
@@ -128,7 +128,7 @@ void board_init_f_init_reserve(ulong base)
*ptr++ = 0;
#endif
/* set GD unless architecture did it already */
-#ifndef CONFIG_X86
+#if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
arch_setup_gd(gd_ptr);
#endif
/* next alloc will be higher by one GD plus 16-byte alignment */
--
2.5.0
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