* [PATCH v2 0/3] arm64: Large PIE fixes
@ 2020-09-04 9:07 Edgar E. Iglesias
2020-09-04 9:07 ` [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help Edgar E. Iglesias
` (2 more replies)
0 siblings, 3 replies; 15+ messages in thread
From: Edgar E. Iglesias @ 2020-09-04 9:07 UTC (permalink / raw)
To: u-boot
From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>
This fixes some builds issues with large (> 1MB) PIE U-boot setups.
We also document the 4K aligned load address requirement and
add an early run-time check for it.
Thanks,
Edgar
ChangeLog:
v1 -> v2:
* Fix adr of _start in arch/arm/lib/crt0_64.S
* Add early check and bail out into a WFI loop when not 4K aligned
* Document the 4K alignement requirement in Kconfig
Edgar E. Iglesias (3):
arm64: Mention 4K aligned load addresses in the PIE Kconfig help
arm64: Bail out PIE builds early if load address is not 4K aligned
arm64: Add support for larger PIE U-boot
arch/arm/Kconfig | 3 +++
arch/arm/cpu/armv8/start.S | 23 +++++++++++++++++++++--
arch/arm/lib/crt0_64.S | 3 ++-
3 files changed, 26 insertions(+), 3 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 15+ messages in thread* [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help 2020-09-04 9:07 [PATCH v2 0/3] arm64: Large PIE fixes Edgar E. Iglesias @ 2020-09-04 9:07 ` Edgar E. Iglesias 2020-09-04 18:42 ` Stephen Warren 2020-09-04 9:07 ` [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned Edgar E. Iglesias 2020-09-04 9:07 ` [PATCH v2 3/3] arm64: Add support for larger PIE U-boot Edgar E. Iglesias 2 siblings, 1 reply; 15+ messages in thread From: Edgar E. Iglesias @ 2020-09-04 9:07 UTC (permalink / raw) To: u-boot From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> Mention the requirement of 4K aligned load addresses in the help section for the POSITION_INDEPENDENT option. Suggested-by: Michal Simek <michal.simek@xilinx.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> --- arch/arm/Kconfig | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index f30c2639ec..c144c08612 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -21,6 +21,9 @@ config POSITION_INDEPENDENT information that is embedded in the binary to support U-Boot relocating itself to the top-of-RAM later during execution. + When this option is enabled, U-Boot needs to be loaded at a + 4K aligned address. + config INIT_SP_RELATIVE bool "Specify the early stack pointer relative to the .bss section" help -- 2.25.1 ^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help 2020-09-04 9:07 ` [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help Edgar E. Iglesias @ 2020-09-04 18:42 ` Stephen Warren 2020-09-06 22:16 ` André Przywara 0 siblings, 1 reply; 15+ messages in thread From: Stephen Warren @ 2020-09-04 18:42 UTC (permalink / raw) To: u-boot On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: > From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > > Mention the requirement of 4K aligned load addresses in the > help section for the POSITION_INDEPENDENT option. > > Suggested-by: Michal Simek <michal.simek@xilinx.com> > Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> > --- > arch/arm/Kconfig | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index f30c2639ec..c144c08612 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -21,6 +21,9 @@ config POSITION_INDEPENDENT > information that is embedded in the binary to support U-Boot > relocating itself to the top-of-RAM later during execution. > > + When this option is enabled, U-Boot needs to be loaded at a > + 4K aligned address. I don't believe this restriction should be documented as part of POSITION_INDEPENDENT; the restriction always exists at least for 64-bit ARM, since arch/arm/lib/relocate_64.S relocate_code uses the same assembly sequence that imposes this restriction, and IIUC that code is unconditionally used. ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help 2020-09-04 18:42 ` Stephen Warren @ 2020-09-06 22:16 ` André Przywara 2020-09-07 9:58 ` Edgar E. Iglesias 0 siblings, 1 reply; 15+ messages in thread From: André Przywara @ 2020-09-06 22:16 UTC (permalink / raw) To: u-boot On 04/09/2020 19:42, Stephen Warren wrote: > On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: >> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> >> >> Mention the requirement of 4K aligned load addresses in the >> help section for the POSITION_INDEPENDENT option. >> >> Suggested-by: Michal Simek <michal.simek@xilinx.com> >> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> >> --- >> arch/arm/Kconfig | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig >> index f30c2639ec..c144c08612 100644 >> --- a/arch/arm/Kconfig >> +++ b/arch/arm/Kconfig >> @@ -21,6 +21,9 @@ config POSITION_INDEPENDENT >> information that is embedded in the binary to support U-Boot >> relocating itself to the top-of-RAM later during execution. >> >> + When this option is enabled, U-Boot needs to be loaded at a >> + 4K aligned address. > > I don't believe this restriction should be documented as part of > POSITION_INDEPENDENT; the restriction always exists at least for 64-bit > ARM, since arch/arm/lib/relocate_64.S relocate_code uses the same > assembly sequence that imposes this restriction, and IIUC that code is > unconditionally used. While this is true, the difference is that without POSITION_INDEPENDENT the alignment is easily determined by the hardcoded load address. So we should actually have a build time check on this. With POSITION_INDEPENDENT, however, the load address is only known at runtime (somewhat under the user's control, if you like). So a warning or hint here might be useful. But maybe it should be noted as a general restriction in the paragraph above: " ... from almost any address" => "from almost any 4K aligned address" Cheers, Andre. ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help 2020-09-06 22:16 ` André Przywara @ 2020-09-07 9:58 ` Edgar E. Iglesias 0 siblings, 0 replies; 15+ messages in thread From: Edgar E. Iglesias @ 2020-09-07 9:58 UTC (permalink / raw) To: u-boot On Sun, Sep 06, 2020 at 11:16:17PM +0100, Andr? Przywara wrote: > On 04/09/2020 19:42, Stephen Warren wrote: > > On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: > >> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > >> > >> Mention the requirement of 4K aligned load addresses in the > >> help section for the POSITION_INDEPENDENT option. > >> > >> Suggested-by: Michal Simek <michal.simek@xilinx.com> > >> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> > >> --- > >> arch/arm/Kconfig | 3 +++ > >> 1 file changed, 3 insertions(+) > >> > >> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > >> index f30c2639ec..c144c08612 100644 > >> --- a/arch/arm/Kconfig > >> +++ b/arch/arm/Kconfig > >> @@ -21,6 +21,9 @@ config POSITION_INDEPENDENT > >> information that is embedded in the binary to support U-Boot > >> relocating itself to the top-of-RAM later during execution. > >> > >> + When this option is enabled, U-Boot needs to be loaded at a > >> + 4K aligned address. > > > > I don't believe this restriction should be documented as part of > > POSITION_INDEPENDENT; the restriction always exists at least for 64-bit > > ARM, since arch/arm/lib/relocate_64.S relocate_code uses the same > > assembly sequence that imposes this restriction, and IIUC that code is > > unconditionally used. > > While this is true, the difference is that without POSITION_INDEPENDENT > the alignment is easily determined by the hardcoded load address. So we > should actually have a build time check on this. > > With POSITION_INDEPENDENT, however, the load address is only known at > runtime (somewhat under the user's control, if you like). So a warning > or hint here might be useful. But maybe it should be noted as a general > restriction in the paragraph above: > " ... from almost any address" => "from almost any 4K aligned address" > That sounds good to me. Thanks, Edgar ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned 2020-09-04 9:07 [PATCH v2 0/3] arm64: Large PIE fixes Edgar E. Iglesias 2020-09-04 9:07 ` [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help Edgar E. Iglesias @ 2020-09-04 9:07 ` Edgar E. Iglesias 2020-09-04 18:43 ` Stephen Warren 2020-09-04 9:07 ` [PATCH v2 3/3] arm64: Add support for larger PIE U-boot Edgar E. Iglesias 2 siblings, 1 reply; 15+ messages in thread From: Edgar E. Iglesias @ 2020-09-04 9:07 UTC (permalink / raw) To: u-boot From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> PIE requires a 4K aligned load address. If this is not met, trap the startup sequence in a WFI loop rather than running into obscure failures. Tested-by: Michal Simek <michal.simek@xilinx.com> Suggested-by: Andr? Przywara <andre.przywara@arm.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> --- arch/arm/cpu/armv8/start.S | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 002698b501..732bc385d4 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -59,6 +59,23 @@ reset: save_boot_params_ret: #if CONFIG_POSITION_INDEPENDENT + /* Verify that we're 4K aligned. */ + adr x1, _start + ands x1, x1, #0xfff + b.eq 1f +0: + /* + * FATAL, can't continue. + * U-boot needs to be loaded at a 4K aligned address. + * + * We use ADRP and ADD to load some symbol addresses during startup. + * The ADD uses an absolute (non pc-relative) lo12 relocation + * thus requiring 4K alignment. + */ + wfi + b 0b +1: + /* * Fix .rela.dyn relocations. This allows U-Boot to be loaded to and * executed at a different address than it was linked at. -- 2.25.1 ^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned 2020-09-04 9:07 ` [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned Edgar E. Iglesias @ 2020-09-04 18:43 ` Stephen Warren 2020-09-07 9:52 ` Edgar E. Iglesias 0 siblings, 1 reply; 15+ messages in thread From: Stephen Warren @ 2020-09-04 18:43 UTC (permalink / raw) To: u-boot On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: > From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > > PIE requires a 4K aligned load address. If this is not met, trap > the startup sequence in a WFI loop rather than running into obscure > failures. > diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S > #if CONFIG_POSITION_INDEPENDENT > + /* Verify that we're 4K aligned. */ Similar to the comment on the previous patch: I believe the code that implements this check should be outside the #if check, since it's always needed. ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned 2020-09-04 18:43 ` Stephen Warren @ 2020-09-07 9:52 ` Edgar E. Iglesias 2020-09-07 12:57 ` Tom Rini 2020-09-08 19:02 ` Stephen Warren 0 siblings, 2 replies; 15+ messages in thread From: Edgar E. Iglesias @ 2020-09-07 9:52 UTC (permalink / raw) To: u-boot On Fri, Sep 04, 2020 at 12:43:57PM -0600, Stephen Warren wrote: > On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: > > From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > > > > PIE requires a 4K aligned load address. If this is not met, trap > > the startup sequence in a WFI loop rather than running into obscure > > failures. > > > diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S > > #if CONFIG_POSITION_INDEPENDENT > > + /* Verify that we're 4K aligned. */ > > Similar to the comment on the previous patch: I believe the code that > implements this check should be outside the #if check, since it's always > needed. But a check for non-PIE would have to be stricter, wouldn't it? I.e the load address needs to exactly match the link-time address. Perhaps we should add the non-PIE check in a separate patch (if at all)? Cheers, Edgar ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned 2020-09-07 9:52 ` Edgar E. Iglesias @ 2020-09-07 12:57 ` Tom Rini 2020-09-07 13:40 ` Edgar E. Iglesias 2020-09-08 19:02 ` Stephen Warren 1 sibling, 1 reply; 15+ messages in thread From: Tom Rini @ 2020-09-07 12:57 UTC (permalink / raw) To: u-boot On Mon, Sep 07, 2020 at 11:52:35AM +0200, Edgar E. Iglesias wrote: > On Fri, Sep 04, 2020 at 12:43:57PM -0600, Stephen Warren wrote: > > On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: > > > From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > > > > > > PIE requires a 4K aligned load address. If this is not met, trap > > > the startup sequence in a WFI loop rather than running into obscure > > > failures. > > > > > diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S > > > #if CONFIG_POSITION_INDEPENDENT > > > + /* Verify that we're 4K aligned. */ > > > > Similar to the comment on the previous patch: I believe the code that > > implements this check should be outside the #if check, since it's always > > needed. > > But a check for non-PIE would have to be stricter, wouldn't it? > I.e the load address needs to exactly match the link-time address. > > Perhaps we should add the non-PIE check in a separate patch (if at all)? If we can catch a bad configuration at link time in the non-PIE case (as said in another part of this thread I believe) then we should, yes, thanks! -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 659 bytes Desc: not available URL: <https://lists.denx.de/pipermail/u-boot/attachments/20200907/4d09778c/attachment.sig> ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned 2020-09-07 12:57 ` Tom Rini @ 2020-09-07 13:40 ` Edgar E. Iglesias 0 siblings, 0 replies; 15+ messages in thread From: Edgar E. Iglesias @ 2020-09-07 13:40 UTC (permalink / raw) To: u-boot On Mon, Sep 07, 2020 at 08:57:39AM -0400, Tom Rini wrote: > On Mon, Sep 07, 2020 at 11:52:35AM +0200, Edgar E. Iglesias wrote: > > On Fri, Sep 04, 2020 at 12:43:57PM -0600, Stephen Warren wrote: > > > On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: > > > > From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > > > > > > > > PIE requires a 4K aligned load address. If this is not met, trap > > > > the startup sequence in a WFI loop rather than running into obscure > > > > failures. > > > > > > > diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S > > > > #if CONFIG_POSITION_INDEPENDENT > > > > + /* Verify that we're 4K aligned. */ > > > > > > Similar to the comment on the previous patch: I believe the code that > > > implements this check should be outside the #if check, since it's always > > > needed. > > > > But a check for non-PIE would have to be stricter, wouldn't it? > > I.e the load address needs to exactly match the link-time address. > > > > Perhaps we should add the non-PIE check in a separate patch (if at all)? > > If we can catch a bad configuration at link time in the non-PIE case (as > said in another part of this thread I believe) then we should, yes, > thanks! The non-PIE configuration is expected to be loaded at a specific address. The actual load address cannot be checked at link-time (since it's up to the user at run-time) but given the assumption of a specific load-address, 4K alignment can be enforced at link-time. It really comes down to adding reasonable run-time checks for errors that users may reasonably struggle with. For PIE, checking for 4K aligment is reasonable because it's an easy enough misstake to make (since you've got a binary that's was supposed to handle relocation). For non-PIE, checking for the exact address at run-time is a little bit more border-line IMO but I guess also somewhat reasonable. There are still plenty of cases we can't catch though (loaded at odd addreses, non-RAM address-ranges etc etc). Cheers, Edgar ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned 2020-09-07 9:52 ` Edgar E. Iglesias 2020-09-07 12:57 ` Tom Rini @ 2020-09-08 19:02 ` Stephen Warren 1 sibling, 0 replies; 15+ messages in thread From: Stephen Warren @ 2020-09-08 19:02 UTC (permalink / raw) To: u-boot On 9/7/20 3:52 AM, Edgar E. Iglesias wrote: > On Fri, Sep 04, 2020 at 12:43:57PM -0600, Stephen Warren wrote: >> On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: >>> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> >>> >>> PIE requires a 4K aligned load address. If this is not met, trap >>> the startup sequence in a WFI loop rather than running into obscure >>> failures. >> >>> diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S >>> #if CONFIG_POSITION_INDEPENDENT >>> + /* Verify that we're 4K aligned. */ >> >> Similar to the comment on the previous patch: I believe the code that >> implements this check should be outside the #if check, since it's always >> needed. > > But a check for non-PIE would have to be stricter, wouldn't it? > I.e the load address needs to exactly match the link-time address. Oh yes, I guess that is true. ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 3/3] arm64: Add support for larger PIE U-boot 2020-09-04 9:07 [PATCH v2 0/3] arm64: Large PIE fixes Edgar E. Iglesias 2020-09-04 9:07 ` [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help Edgar E. Iglesias 2020-09-04 9:07 ` [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned Edgar E. Iglesias @ 2020-09-04 9:07 ` Edgar E. Iglesias 2020-09-04 13:04 ` Michal Simek 2020-09-04 18:45 ` Stephen Warren 2 siblings, 2 replies; 15+ messages in thread From: Edgar E. Iglesias @ 2020-09-04 9:07 UTC (permalink / raw) To: u-boot From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> Linking a U-boot larger than 1MB fails with PIE enabled: u-boot/arch/arm/cpu/armv8/start.S:71:(.text+0x3c): relocation truncated to fit: R_AARCH64_ADR_PREL_LO21 against symbol `__rel_dyn_end' defined in .bss_start section in u-boot. This extends the supported range by using adrp & add to load symbols early while starting up. Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> --- arch/arm/cpu/armv8/start.S | 6 ++++-- arch/arm/lib/crt0_64.S | 3 ++- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 732bc385d4..335783014c 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -84,8 +84,10 @@ pie_fixup: adr x0, _start /* x0 <- Runtime value of _start */ ldr x1, _TEXT_BASE /* x1 <- Linked value of _start */ sub x9, x0, x1 /* x9 <- Run-vs-link offset */ - adr x2, __rel_dyn_start /* x2 <- Runtime &__rel_dyn_start */ - adr x3, __rel_dyn_end /* x3 <- Runtime &__rel_dyn_end */ + adrp x2, __rel_dyn_start /* x2 <- Runtime &__rel_dyn_start */ + add x2, x2, #:lo12:__rel_dyn_start + adrp x3, __rel_dyn_end /* x3 <- Runtime &__rel_dyn_end */ + add x3, x3, #:lo12:__rel_dyn_end pie_fix_loop: ldp x0, x1, [x2], #16 /* (x0, x1) <- (Link location, fixup) */ ldr x4, [x2], #8 /* x4 <- addend */ diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S index 04afa518ac..f28071a238 100644 --- a/arch/arm/lib/crt0_64.S +++ b/arch/arm/lib/crt0_64.S @@ -102,7 +102,8 @@ ENTRY(_main) adr lr, relocation_return #if CONFIG_POSITION_INDEPENDENT /* Add in link-vs-runtime offset */ - adr x0, _start /* x0 <- Runtime value of _start */ + adrp x0, _start /* x0 <- Runtime value of _start */ + add x0, x0, #:lo12:_start ldr x9, _TEXT_BASE /* x9 <- Linked value of _start */ sub x9, x9, x0 /* x9 <- Run-vs-link offset */ add lr, lr, x9 -- 2.25.1 ^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH v2 3/3] arm64: Add support for larger PIE U-boot 2020-09-04 9:07 ` [PATCH v2 3/3] arm64: Add support for larger PIE U-boot Edgar E. Iglesias @ 2020-09-04 13:04 ` Michal Simek 2020-09-04 13:11 ` Edgar E. Iglesias 2020-09-04 18:45 ` Stephen Warren 1 sibling, 1 reply; 15+ messages in thread From: Michal Simek @ 2020-09-04 13:04 UTC (permalink / raw) To: u-boot On 04. 09. 20 11:07, Edgar E. Iglesias wrote: > From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > > Linking a U-boot larger than 1MB fails with PIE enabled: > u-boot/arch/arm/cpu/armv8/start.S:71:(.text+0x3c): relocation > truncated to fit: R_AARCH64_ADR_PREL_LO21 against symbol `__rel_dyn_end' > defined in .bss_start section in u-boot. > > This extends the supported range by using adrp & add to load symbols > early while starting up. > > Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> > --- > arch/arm/cpu/armv8/start.S | 6 ++++-- > arch/arm/lib/crt0_64.S | 3 ++- > 2 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S > index 732bc385d4..335783014c 100644 > --- a/arch/arm/cpu/armv8/start.S > +++ b/arch/arm/cpu/armv8/start.S > @@ -84,8 +84,10 @@ pie_fixup: > adr x0, _start /* x0 <- Runtime value of _start */ > ldr x1, _TEXT_BASE /* x1 <- Linked value of _start */ > sub x9, x0, x1 /* x9 <- Run-vs-link offset */ > - adr x2, __rel_dyn_start /* x2 <- Runtime &__rel_dyn_start */ > - adr x3, __rel_dyn_end /* x3 <- Runtime &__rel_dyn_end */ > + adrp x2, __rel_dyn_start /* x2 <- Runtime &__rel_dyn_start */ > + add x2, x2, #:lo12:__rel_dyn_start > + adrp x3, __rel_dyn_end /* x3 <- Runtime &__rel_dyn_end */ > + add x3, x3, #:lo12:__rel_dyn_end > pie_fix_loop: > ldp x0, x1, [x2], #16 /* (x0, x1) <- (Link location, fixup) */ > ldr x4, [x2], #8 /* x4 <- addend */ > diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S > index 04afa518ac..f28071a238 100644 > --- a/arch/arm/lib/crt0_64.S > +++ b/arch/arm/lib/crt0_64.S > @@ -102,7 +102,8 @@ ENTRY(_main) > adr lr, relocation_return > #if CONFIG_POSITION_INDEPENDENT > /* Add in link-vs-runtime offset */ > - adr x0, _start /* x0 <- Runtime value of _start */ > + adrp x0, _start /* x0 <- Runtime value of _start */ > + add x0, x0, #:lo12:_start > ldr x9, _TEXT_BASE /* x9 <- Linked value of _start */ > sub x9, x9, x0 /* x9 <- Run-vs-link offset */ > add lr, lr, x9 > I have tested 21MB and 51MB u-boot and there is need to also patch __bss_start. --- a/arch/arm/lib/crt0_64.S +++ b/arch/arm/lib/crt0_64.S @@ -73,7 +73,12 @@ ENTRY(_main) #elif defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK) ldr x0, =(CONFIG_SPL_STACK) #elif defined(CONFIG_INIT_SP_RELATIVE) +#if CONFIG_POSITION_INDEPENDENT + adrp x0, __bss_start /* x0 <- Runtime &__bss_start */ + add x0, x0, #:lo12:__bss_start +#else adr x0, __bss_start +#endif add x0, x0, #CONFIG_SYS_INIT_SP_BSS_OFFSET #else ldr x0, =(CONFIG_SYS_INIT_SP_ADDR) Thanks, Michal ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 3/3] arm64: Add support for larger PIE U-boot 2020-09-04 13:04 ` Michal Simek @ 2020-09-04 13:11 ` Edgar E. Iglesias 0 siblings, 0 replies; 15+ messages in thread From: Edgar E. Iglesias @ 2020-09-04 13:11 UTC (permalink / raw) To: u-boot On Fri, Sep 04, 2020 at 03:04:02PM +0200, Michal Simek wrote: > > > On 04. 09. 20 11:07, Edgar E. Iglesias wrote: > > From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > > > > Linking a U-boot larger than 1MB fails with PIE enabled: > > u-boot/arch/arm/cpu/armv8/start.S:71:(.text+0x3c): relocation > > truncated to fit: R_AARCH64_ADR_PREL_LO21 against symbol `__rel_dyn_end' > > defined in .bss_start section in u-boot. > > > > This extends the supported range by using adrp & add to load symbols > > early while starting up. > > > > Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> > > --- > > arch/arm/cpu/armv8/start.S | 6 ++++-- > > arch/arm/lib/crt0_64.S | 3 ++- > > 2 files changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S > > index 732bc385d4..335783014c 100644 > > --- a/arch/arm/cpu/armv8/start.S > > +++ b/arch/arm/cpu/armv8/start.S > > @@ -84,8 +84,10 @@ pie_fixup: > > adr x0, _start /* x0 <- Runtime value of _start */ > > ldr x1, _TEXT_BASE /* x1 <- Linked value of _start */ > > sub x9, x0, x1 /* x9 <- Run-vs-link offset */ > > - adr x2, __rel_dyn_start /* x2 <- Runtime &__rel_dyn_start */ > > - adr x3, __rel_dyn_end /* x3 <- Runtime &__rel_dyn_end */ > > + adrp x2, __rel_dyn_start /* x2 <- Runtime &__rel_dyn_start */ > > + add x2, x2, #:lo12:__rel_dyn_start > > + adrp x3, __rel_dyn_end /* x3 <- Runtime &__rel_dyn_end */ > > + add x3, x3, #:lo12:__rel_dyn_end > > pie_fix_loop: > > ldp x0, x1, [x2], #16 /* (x0, x1) <- (Link location, fixup) */ > > ldr x4, [x2], #8 /* x4 <- addend */ > > diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S > > index 04afa518ac..f28071a238 100644 > > --- a/arch/arm/lib/crt0_64.S > > +++ b/arch/arm/lib/crt0_64.S > > @@ -102,7 +102,8 @@ ENTRY(_main) > > adr lr, relocation_return > > #if CONFIG_POSITION_INDEPENDENT > > /* Add in link-vs-runtime offset */ > > - adr x0, _start /* x0 <- Runtime value of _start */ > > + adrp x0, _start /* x0 <- Runtime value of _start */ > > + add x0, x0, #:lo12:_start > > ldr x9, _TEXT_BASE /* x9 <- Linked value of _start */ > > sub x9, x9, x0 /* x9 <- Run-vs-link offset */ > > add lr, lr, x9 > > > > I have tested 21MB and 51MB u-boot and there is need to also patch > __bss_start. > > > --- a/arch/arm/lib/crt0_64.S > +++ b/arch/arm/lib/crt0_64.S > @@ -73,7 +73,12 @@ ENTRY(_main) > #elif defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK) > ldr x0, =(CONFIG_SPL_STACK) > #elif defined(CONFIG_INIT_SP_RELATIVE) > +#if CONFIG_POSITION_INDEPENDENT > + adrp x0, __bss_start /* x0 <- Runtime &__bss_start */ > + add x0, x0, #:lo12:__bss_start > +#else > adr x0, __bss_start > +#endif > add x0, x0, #CONFIG_SYS_INIT_SP_BSS_OFFSET > #else > ldr x0, =(CONFIG_SYS_INIT_SP_ADDR) > Thanks Michal, I can bundle this into v3. Cheers, Edgar ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 3/3] arm64: Add support for larger PIE U-boot 2020-09-04 9:07 ` [PATCH v2 3/3] arm64: Add support for larger PIE U-boot Edgar E. Iglesias 2020-09-04 13:04 ` Michal Simek @ 2020-09-04 18:45 ` Stephen Warren 1 sibling, 0 replies; 15+ messages in thread From: Stephen Warren @ 2020-09-04 18:45 UTC (permalink / raw) To: u-boot On 9/4/20 3:07 AM, Edgar E. Iglesias wrote: > From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com> > > Linking a U-boot larger than 1MB fails with PIE enabled: > u-boot/arch/arm/cpu/armv8/start.S:71:(.text+0x3c): relocation > truncated to fit: R_AARCH64_ADR_PREL_LO21 against symbol `__rel_dyn_end' > defined in .bss_start section in u-boot. > > This extends the supported range by using adrp & add to load symbols > early while starting up. This patch looks conceptually fine to me, but I won't ack this version due to the issue pointed out by Michal. ^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2020-09-08 19:02 UTC | newest] Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-09-04 9:07 [PATCH v2 0/3] arm64: Large PIE fixes Edgar E. Iglesias 2020-09-04 9:07 ` [PATCH v2 1/3] arm64: Mention 4K aligned load addresses in the PIE Kconfig help Edgar E. Iglesias 2020-09-04 18:42 ` Stephen Warren 2020-09-06 22:16 ` André Przywara 2020-09-07 9:58 ` Edgar E. Iglesias 2020-09-04 9:07 ` [PATCH v2 2/3] arm64: Bail out PIE builds early if load address is not 4K aligned Edgar E. Iglesias 2020-09-04 18:43 ` Stephen Warren 2020-09-07 9:52 ` Edgar E. Iglesias 2020-09-07 12:57 ` Tom Rini 2020-09-07 13:40 ` Edgar E. Iglesias 2020-09-08 19:02 ` Stephen Warren 2020-09-04 9:07 ` [PATCH v2 3/3] arm64: Add support for larger PIE U-boot Edgar E. Iglesias 2020-09-04 13:04 ` Michal Simek 2020-09-04 13:11 ` Edgar E. Iglesias 2020-09-04 18:45 ` Stephen Warren
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.