If both POSITION_INDEPENDENT and SYS_RELOC_GD_ENV_ADDR are enabled, wherever original env is placed anywhere, it should be relocated to the right address.
Relocation offset gd->reloc_off is calculated with SYS_TEXT_BASE in setup_reloc() and env address gd->env_addr is relocated by the offset in initr_reloc_global_data().
gd->env_addr = (orig env) + gd->reloc_off = (orig env) + (gd->relocaddr - SYS_TEXT_BASE)
However, SYS_TEXT_BASE isn't always runtime base address when POSITION_INDEPENDENT is enabled. So the relocated env_addr might point to wrong address. For example, if SYS_TEXT_BASE is zero, gd->env_addr is out of memory location and memory exception will occur.
There is a difference between linked address such as SYS_TEXT_BASE and runtime base address. In _main, the difference is calculated as "run-vs-link" offset. The env_addr should also be added to the offset to fix the address.
gd->env_addr = (orig env) + ("run-vs-link" offset) + gd->reloc_off = (orig env) + (SYS_TEXT_BASE - _start) + (gd->relocaddr - SYS_TEXT_BASE) = (orig env) + (gd->relocaddr - _start)
Cc: Marek Vasut marex@denx.de Signed-off-by: Kunihiko Hayashi hayashi.kunihiko@socionext.com --- arch/arm/lib/crt0_64.S | 5 +++++ lib/asm-offsets.c | 2 ++ 2 files changed, 7 insertions(+)
This patch is based on the previous topic: "env: Leave invalid env for nowhere location" https://patchwork.ozlabs.org/project/uboot/patch/1620828554-24013-1-git-send...
diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S index 9d2319c..680e674 100644 --- a/arch/arm/lib/crt0_64.S +++ b/arch/arm/lib/crt0_64.S @@ -112,6 +112,11 @@ ENTRY(_main) ldr x9, _TEXT_BASE /* x9 <- Linked value of _start */ sub x9, x9, x0 /* x9 <- Run-vs-link offset */ add lr, lr, x9 +#if defined(CONFIG_SYS_RELOC_GD_ENV_ADDR) + ldr x0, [x18, #GD_ENV_ADDR] /* x0 <- gd->env_addr */ + add x0, x0, x9 + str x0, [x18, #GD_ENV_ADDR] +#endif #endif /* Add in link-vs-relocation offset */ ldr x9, [x18, #GD_RELOC_OFF] /* x9 <- gd->reloc_off */ diff --git a/lib/asm-offsets.c b/lib/asm-offsets.c index ee592cf..c691066 100644 --- a/lib/asm-offsets.c +++ b/lib/asm-offsets.c @@ -41,5 +41,7 @@ int main(void)
DEFINE(GD_NEW_GD, offsetof(struct global_data, new_gd));
+ DEFINE(GD_ENV_ADDR, offsetof(struct global_data, env_addr)); + return 0; }