| Message ID | 1623738782-10072-1-git-send-email-hayashi.kunihiko@socionext.com |
|---|---|
| State | Accepted |
| Commit | 534f0fbd65203871c2b054096422a5d0f3346cb1 |
| Headers | show |
| Series | arm64: Fix relocation of env_addr if POSITION_INDEPENDENT=y | expand |
On 6/15/21 8:33 AM, Kunihiko Hayashi wrote: > 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> Thank you for debugging and fixing this properly. Acked-by: Marek Vasut <marex@denx.de> Tested-by: Marek Vasut <marex@denx.de> I did manage to reproduce it on RCar3, and this patch fixes the crash on boot indeed. Tom, it would be good to include it in this release too.
On Tue, Jun 15, 2021 at 03:33:02PM +0900, Kunihiko Hayashi wrote: > 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> > Acked-by: Marek Vasut <marex@denx.de> > Tested-by: Marek Vasut <marex@denx.de> Applied to u-boot/master, thanks! -- Tom
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; }
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-email-hayashi.kunihiko@socionext.com/ -- 2.7.4