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| author | Julius Baxter <juliusbaxter@gmail.com> | 2012-05-05 12:32:11 +0000 |
|---|---|---|
| committer | Wolfgang Denk <wd@denx.de> | 2012-08-09 23:37:45 +0200 |
| commit | 3874a377451e4d1f45710f5bf801dd96e8b8f67e (patch) | |
| tree | c9ecb29bc7b72a91affc6ab25e8950cb5ebc483c /arch/openrisc | |
| parent | eb0b43f264077fb7ff53b479dce76324a8aaa696 (diff) | |
| download | blackbird-obmc-uboot-3874a377451e4d1f45710f5bf801dd96e8b8f67e.tar.gz blackbird-obmc-uboot-3874a377451e4d1f45710f5bf801dd96e8b8f67e.zip | |
openrisc: Work around potential relocation issues
When reset code is in flash, the jump instructions emitted by the
compiler are relative instead of absolute jumps.
A fix to the reset code to make correct jumps to the beginning of
code relocated to RAM have also been added.
Signed-off-by: Julius Baxter <juliusbaxter@gmail.com>
Diffstat (limited to 'arch/openrisc')
| -rw-r--r-- | arch/openrisc/cpu/cpu.c | 6 | ||||
| -rw-r--r-- | arch/openrisc/cpu/start.S | 13 |
2 files changed, 13 insertions, 6 deletions
diff --git a/arch/openrisc/cpu/cpu.c b/arch/openrisc/cpu/cpu.c index 25cd6249d2..73ecc6f766 100644 --- a/arch/openrisc/cpu/cpu.c +++ b/arch/openrisc/cpu/cpu.c @@ -151,7 +151,11 @@ extern void __reset(void); int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { disable_interrupts(); - __reset(); + /* Code the jump to __reset here as the compiler is prone to + emitting a bad jump instruction if the function is in flash */ + __asm__("l.movhi r1,hi(__reset); \ + l.ori r1,r1,lo(__reset); \ + l.jr r1"); /* not reached, __reset does not return */ return 0; } diff --git a/arch/openrisc/cpu/start.S b/arch/openrisc/cpu/start.S index 3a4271750e..39c80e134f 100644 --- a/arch/openrisc/cpu/start.S +++ b/arch/openrisc/cpu/start.S @@ -26,8 +26,11 @@ #define HANDLE_EXCEPTION \ l.addi r1, r1, -EXCEPTION_STACK_SIZE ;\ + l.sw 0x00(r1), r2 ;\ l.sw 0x1c(r1), r9 ;\ - l.jal _exception_handler ;\ + l.movhi r2,hi(_exception_handler) ;\ + l.ori r2,r2,lo(_exception_handler) ;\ + l.jalr r2 ;\ l.nop ;\ l.lwz r9, 0x1c(r1) ;\ l.addi r1, r1, EXCEPTION_STACK_SIZE ;\ @@ -79,8 +82,9 @@ __reset: l.bnf .L_relocvectors l.addi r4,r4, 4 #endif - - l.j _start + l.movhi r4,hi(_start) + l.ori r4,r4,lo(_start) + l.jr r4 l.nop /* bus error */ @@ -262,8 +266,7 @@ _start: .type _exception_handler,@function _exception_handler: - /* Store state (r9 already saved)*/ - l.sw 0x00(r1), r2 + /* Store state (r2 and r9 already saved)*/ l.sw 0x04(r1), r3 l.sw 0x08(r1), r4 l.sw 0x0c(r1), r5 |
