[U-Boot] [PATCH] imx: Fix potential lmb memory overwritten by stack
Ye Li
ye.li at nxp.com
Fri Jan 4 09:10:20 UTC 2019
At default, u-boot reserves the memory from SP - 4KB to DRAM end for
lmb in arch_lmb_reserve. So lmb won't allocate any memory from it.
But we found the 4K gap for SP is not enough now, because some FDT
updating operations are added in our u-boot before jumping to kernel,
which needs larger stack. This causes the lmb allocated memory is overwritten
by stack.
Fix the issue by implementing the board_lmb_reserve to reserve from
SP - 16KB to memory end for lmb.
Signed-off-by: Ye Li <ye.li at nxp.com>
---
arch/arm/mach-imx/misc.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/arch/arm/mach-imx/misc.c b/arch/arm/mach-imx/misc.c
index 1bb8c50..31e95a9 100644
--- a/arch/arm/mach-imx/misc.c
+++ b/arch/arm/mach-imx/misc.c
@@ -9,6 +9,8 @@
#include <asm/io.h>
#include <asm/mach-imx/regs-common.h>
+DECLARE_GLOBAL_DATA_PTR;
+
/* 1 second delay should be plenty of time for block reset. */
#define RESET_MAX_TIMEOUT 1000000
@@ -71,3 +73,33 @@ int mxs_reset_block(struct mxs_register_32 *reg)
return 0;
}
+
+static ulong get_sp(void)
+{
+ ulong ret;
+
+ asm("mov %0, sp" : "=r"(ret) : );
+ return ret;
+}
+
+void board_lmb_reserve(struct lmb *lmb)
+{
+ ulong sp, bank_end;
+ int bank;
+
+ sp = get_sp();
+ debug("## Current stack ends at 0x%08lx ", sp);
+
+ /* adjust sp by 16K to be safe */
+ sp -= 4096 << 2;
+ for (bank = 0; bank < CONFIG_NR_DRAM_BANKS; bank++) {
+ if (sp < gd->bd->bi_dram[bank].start)
+ continue;
+ bank_end = gd->bd->bi_dram[bank].start +
+ gd->bd->bi_dram[bank].size;
+ if (sp >= bank_end)
+ continue;
+ lmb_reserve(lmb, sp, bank_end - sp);
+ break;
+ }
+}
--
2.7.4
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