Messages in this thread Patch in this message | | | From | Ard Biesheuvel <> | Date | Fri, 28 Apr 2023 19:16:55 +0100 | Subject | Re: [PATCH] arm64: kernel: remove SHF_WRITE|SHF_EXECINSTR from .idmap.text |
| |
Hi Nick,
On Fri, 28 Apr 2023 at 19:09, <ndesaulniers@google.com> wrote: > > commit d54170812ef1 ("arm64: fix .idmap.text assertion for large kernels") > modified some of the section assembler directives that declare > .idmap.text to be SHF_ALLOC instead of > SHF_ALLOC|SHF_WRITE|SHF_EXECINSTR. > > This patch fixes up the remaining stragglers that were left behind. > > Because .idmap.text is merged into .text,
Nit: this is no longer the case: the ID map code is never executed via the kernel mapping, so we moved it into a special .rodata.text section that contains all generated code that should not have an executable mapping by default, but only when it gets copied and/or mapped into a different executable region.
This doesn't impact the correctness of the patch, so with this paragraph clarified:
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
> LLD will retain the > SHF_EXECINSTR on .text, in addition to the synthetic .got. This doesn't > matter to the kernel loader, but syzkaller is having trouble symboling > such sections. Clean this up while we additionally fix up syzkaller. Add > Fixes tag so that this doesn't precede related change in stable. > > Fixes: d54170812ef1 ("arm64: fix .idmap.text assertion for large kernels") > Reported-by: Greg Thelen <gthelen@google.com> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > --- > arch/arm64/kernel/cpu-reset.S | 2 +- > arch/arm64/kernel/sleep.S | 2 +- > arch/arm64/mm/proc.S | 6 +++--- > 3 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S > index 6b752fe89745..c87445dde674 100644 > --- a/arch/arm64/kernel/cpu-reset.S > +++ b/arch/arm64/kernel/cpu-reset.S > @@ -14,7 +14,7 @@ > #include <asm/virt.h> > > .text > -.pushsection .idmap.text, "awx" > +.pushsection .idmap.text, "a" > > /* > * cpu_soft_restart(el2_switch, entry, arg0, arg1, arg2) > diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S > index 2ae7cff1953a..2aa5129d8253 100644 > --- a/arch/arm64/kernel/sleep.S > +++ b/arch/arm64/kernel/sleep.S > @@ -97,7 +97,7 @@ SYM_FUNC_START(__cpu_suspend_enter) > ret > SYM_FUNC_END(__cpu_suspend_enter) > > - .pushsection ".idmap.text", "awx" > + .pushsection ".idmap.text", "a" > SYM_CODE_START(cpu_resume) > mov x0, xzr > bl init_kernel_el > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > index 91410f488090..c2cb437821ca 100644 > --- a/arch/arm64/mm/proc.S > +++ b/arch/arm64/mm/proc.S > @@ -167,7 +167,7 @@ alternative_else_nop_endif > SYM_FUNC_END(cpu_do_resume) > #endif > > - .pushsection ".idmap.text", "awx" > + .pushsection ".idmap.text", "a" > > .macro __idmap_cpu_set_reserved_ttbr1, tmp1, tmp2 > adrp \tmp1, reserved_pg_dir > @@ -201,7 +201,7 @@ SYM_FUNC_END(idmap_cpu_replace_ttbr1) > > #define KPTI_NG_PTE_FLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) > > - .pushsection ".idmap.text", "awx" > + .pushsection ".idmap.text", "a" > > .macro kpti_mk_tbl_ng, type, num_entries > add end_\type\()p, cur_\type\()p, #\num_entries * 8 > @@ -400,7 +400,7 @@ SYM_FUNC_END(idmap_kpti_install_ng_mappings) > * Output: > * Return in x0 the value of the SCTLR_EL1 register. > */ > - .pushsection ".idmap.text", "awx" > + .pushsection ".idmap.text", "a" > SYM_FUNC_START(__cpu_setup) > tlbi vmalle1 // Invalidate local TLB > dsb nsh > > --- > base-commit: 22b8cc3e78f5448b4c5df00303817a9137cd663f > change-id: 20230428-awx-c73f4bde79c4 > > Best regards, > -- > Nick Desaulniers <ndesaulniers@google.com> >
| |