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| author | Oleksij Rempel <o.rempel@pengutronix.de> | 2020-01-30 08:38:57 +0100 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2020-02-03 09:17:53 +0100 |
| commit | c622c8be4ee14454bc3590735af8be6ca5e989fe (patch) | |
| tree | 9f101bd3b5dcce251e2b0de245f2323f264f4709 /arch/mips/lib | |
| parent | b7a9e582c393e8fcd1e22044dd7384734d9e5a7a (diff) | |
| download | barebox-c622c8be4ee14454bc3590735af8be6ca5e989fe.tar.gz barebox-c622c8be4ee14454bc3590735af8be6ca5e989fe.tar.xz | |
MIPS: don't overlay relocation data with BSS
.bss __rel_start (OVERLAY) was used to optimize RAM size used by
barebox. Since .bss and __rel_start overlap, we should clear bss only
after __rel_start was used. Following patch changed initialization
sequence to clear .bss before __rel_start:
1e5aef61fc6a444 ("MIPS: reloc: init bss and cpu")
This make relocation buffer unusable and broke relocation with different
symptoms reported by Antony Pavlov <antonynpavlov@gmail.com>:
* iomem output has no information on sdram regions, so memtest is unusable;
* pc = 0xa081232c, relocation does not work, barebox is located with 8M offset
from start of RAM. The board has 256M and relocation routine
should move barebox code much higher;
* pc = 0xa081232c, so barebox code works from KSEG1 not from KSEG0 as MMU=y option implies.
There is a choice of moving .bss clear sequence after __rel_start or
remove this optimization. Since the use of this optimization is minimal
and danger to trap in to similar issue is still high, i prefer to remove
this optimization.
As result of this change, we need to fix calculation of relocation are
size:
relocate_code() calculates relocation area size as a sum (barebox_image_size +
bss_len). barebox_image_size and bss_len are calculated as (__image_end -
__image_start) and (__bss_stop - __bss_start) respectively. This doesn't take
into account relocation data placed between __image_end and __bss_start.
However relocation preserves BSS position relative to image start, as if
relocation data is still there. This causes RAM overflow during BSS
initialization in main_entry(). This problem may be hidden due to the alignment
of the `relocaddr`.
Reported-by: Antony Pavlov <antonynpavlov@gmail.com>
Fixes: 1e5aef61fc6a444 ("MIPS: reloc: init bss and cpu")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Peter Mamonov <pmamonov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'arch/mips/lib')
| -rw-r--r-- | arch/mips/lib/barebox.lds.S | 2 | ||||
| -rw-r--r-- | arch/mips/lib/reloc.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/mips/lib/barebox.lds.S b/arch/mips/lib/barebox.lds.S index 693a778980..c954df41f3 100644 --- a/arch/mips/lib/barebox.lds.S +++ b/arch/mips/lib/barebox.lds.S @@ -59,7 +59,7 @@ SECTIONS _end = .; - .bss __rel_start (OVERLAY) : { + .bss : { __bss_start = .; *(.sbss.*) *(.bss.*) diff --git a/arch/mips/lib/reloc.c b/arch/mips/lib/reloc.c index df9760e38c..4b0e252352 100644 --- a/arch/mips/lib/reloc.c +++ b/arch/mips/lib/reloc.c @@ -118,7 +118,7 @@ void relocate_code(void *fdt, u32 fdt_size, u32 ram_size) memset(__bss_start, 0, bss_len); cpu_probe(); - length = barebox_image_size + bss_len; + length = __bss_stop - __image_start; relocaddr = ALIGN_DOWN(ram_size - length, SZ_64K); relocaddr = KSEG0ADDR(relocaddr); new_stack = relocaddr - MALLOC_SIZE - 16; |