From c622c8be4ee14454bc3590735af8be6ca5e989fe Mon Sep 17 00:00:00 2001 From: Oleksij Rempel Date: Thu, 30 Jan 2020 08:38:57 +0100 Subject: 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 : * 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 Fixes: 1e5aef61fc6a444 ("MIPS: reloc: init bss and cpu") Signed-off-by: Oleksij Rempel Signed-off-by: Peter Mamonov Signed-off-by: Sascha Hauer --- arch/mips/lib/reloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/mips/lib/reloc.c') 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; -- cgit v1.2.3