From: Ard Biesheuvel <ardb@kernel.org>
init_pgdir[] is only referenced from the startup code, but lives after
BSS in the linker map. Before tightening the rules about accessing BSS
from startup code, move init_pgdir[] into the __pi_ namespace, so it
does not need to be exported explicitly.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/include/asm/pgtable.h | 2 --
arch/arm64/kernel/image-vars.h | 2 --
arch/arm64/kernel/pi/pi.h | 1 +
arch/arm64/kernel/vmlinux.lds.S | 4 ++--
4 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index d3b538be1500..6a040f0bbfe1 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -754,8 +754,6 @@ static inline bool pud_table(pud_t pud) { return true; }
PUD_TYPE_TABLE)
#endif
-extern pgd_t init_pg_dir[];
-extern pgd_t init_pg_end[];
extern pgd_t swapper_pg_dir[];
extern pgd_t idmap_pg_dir[];
extern pgd_t tramp_pg_dir[];
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 5e3c4b58f279..a0977f7cd3ec 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -56,8 +56,6 @@ PROVIDE(__pi_memstart_offset_seed = memstart_offset_seed);
PROVIDE(__pi_init_idmap_pg_dir = init_idmap_pg_dir);
PROVIDE(__pi_init_idmap_pg_end = init_idmap_pg_end);
-PROVIDE(__pi_init_pg_dir = init_pg_dir);
-PROVIDE(__pi_init_pg_end = init_pg_end);
PROVIDE(__pi_swapper_pg_dir = swapper_pg_dir);
PROVIDE(__pi__text = _text);
diff --git a/arch/arm64/kernel/pi/pi.h b/arch/arm64/kernel/pi/pi.h
index c91e5e965cd3..38a908d048e8 100644
--- a/arch/arm64/kernel/pi/pi.h
+++ b/arch/arm64/kernel/pi/pi.h
@@ -22,6 +22,7 @@ static inline void *prel64_to_pointer(const prel64_t *offset)
extern bool dynamic_scs_is_enabled;
extern pgd_t init_idmap_pg_dir[], init_idmap_pg_end[];
+extern pgd_t init_pg_dir[];
void init_feature_override(u64 boot_status, const void *fdt, int chosen);
u64 kaslr_early_init(void *fdt, int chosen);
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index e73326bd3ff7..73fa57f341b0 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -321,9 +321,9 @@ SECTIONS
BSS_SECTION(SBSS_ALIGN, 0, 0)
. = ALIGN(PAGE_SIZE);
- init_pg_dir = .;
+ __pi_init_pg_dir = .;
. += INIT_DIR_SIZE;
- init_pg_end = .;
+ __pi_init_pg_end = .;
/* end of zero-init region */
. += SZ_4K; /* stack for the early C runtime */
--
2.49.0.906.g1f30a19c02-googHi Ard,
kernel test robot noticed the following build errors:
[auto build test ERROR on soc/for-next]
[also build test ERROR on arm/for-next arm/fixes linus/master v6.15-rc5 next-20250505]
[cannot apply to arm64/for-next/core kvmarm/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Ard-Biesheuvel/arm64-boot-Move-init_pgdir-into-__pi_-namespace/20250503-192534
base: https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
patch link: https://lore.kernel.org/r/20250503112137.1962910-6-ardb%2Bgit%40google.com
patch subject: [PATCH 1/3] arm64/boot: Move init_pgdir[] into __pi_ namespace
config: arm64-allnoconfig (https://download.01.org/0day-ci/archive/20250506/202505060740.OIkWGFVZ-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250506/202505060740.OIkWGFVZ-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505060740.OIkWGFVZ-lkp@intel.com/
All errors (new ones prefixed by >>):
arch/arm64/kernel/pi/map_kernel.c: In function 'remap_idmap_for_lpa2':
>> arch/arm64/kernel/pi/map_kernel.c:191:37: error: 'init_pg_end' undeclared (first use in this function); did you mean 'init_pg_dir'?
191 | memset(init_pg_dir, 0, (u64)init_pg_end - (u64)init_pg_dir);
| ^~~~~~~~~~~
| init_pg_dir
arch/arm64/kernel/pi/map_kernel.c:191:37: note: each undeclared identifier is reported only once for each function it appears in
arch/arm64/kernel/pi/map_kernel.c: In function 'early_map_kernel':
arch/arm64/kernel/pi/map_kernel.c:222:37: error: 'init_pg_end' undeclared (first use in this function); did you mean 'init_pg_dir'?
222 | memset(__bss_start, 0, (u64)init_pg_end - (u64)__bss_start);
| ^~~~~~~~~~~
| init_pg_dir
vim +191 arch/arm64/kernel/pi/map_kernel.c
9684ec186f8fad Ard Biesheuvel 2024-02-14 158
9684ec186f8fad Ard Biesheuvel 2024-02-14 159 static void __init remap_idmap_for_lpa2(void)
9684ec186f8fad Ard Biesheuvel 2024-02-14 160 {
9684ec186f8fad Ard Biesheuvel 2024-02-14 161 /* clear the bits that change meaning once LPA2 is turned on */
9684ec186f8fad Ard Biesheuvel 2024-02-14 162 pteval_t mask = PTE_SHARED;
9684ec186f8fad Ard Biesheuvel 2024-02-14 163
9684ec186f8fad Ard Biesheuvel 2024-02-14 164 /*
9684ec186f8fad Ard Biesheuvel 2024-02-14 165 * We have to clear bits [9:8] in all block or page descriptors in the
9684ec186f8fad Ard Biesheuvel 2024-02-14 166 * initial ID map, as otherwise they will be (mis)interpreted as
9684ec186f8fad Ard Biesheuvel 2024-02-14 167 * physical address bits once we flick the LPA2 switch (TCR.DS). Since
9684ec186f8fad Ard Biesheuvel 2024-02-14 168 * we cannot manipulate live descriptors in that way without creating
9684ec186f8fad Ard Biesheuvel 2024-02-14 169 * potential TLB conflicts, let's create another temporary ID map in a
9684ec186f8fad Ard Biesheuvel 2024-02-14 170 * LPA2 compatible fashion, and update the initial ID map while running
9684ec186f8fad Ard Biesheuvel 2024-02-14 171 * from that.
9684ec186f8fad Ard Biesheuvel 2024-02-14 172 */
9684ec186f8fad Ard Biesheuvel 2024-02-14 173 create_init_idmap(init_pg_dir, mask);
9684ec186f8fad Ard Biesheuvel 2024-02-14 174 dsb(ishst);
9684ec186f8fad Ard Biesheuvel 2024-02-14 175 set_ttbr0_for_lpa2((u64)init_pg_dir);
9684ec186f8fad Ard Biesheuvel 2024-02-14 176
9684ec186f8fad Ard Biesheuvel 2024-02-14 177 /*
9684ec186f8fad Ard Biesheuvel 2024-02-14 178 * Recreate the initial ID map with the same granularity as before.
9684ec186f8fad Ard Biesheuvel 2024-02-14 179 * Don't bother with the FDT, we no longer need it after this.
9684ec186f8fad Ard Biesheuvel 2024-02-14 180 */
9684ec186f8fad Ard Biesheuvel 2024-02-14 181 memset(init_idmap_pg_dir, 0,
ecc54006f158ae Zenghui Yu 2024-06-21 182 (u64)init_idmap_pg_end - (u64)init_idmap_pg_dir);
9684ec186f8fad Ard Biesheuvel 2024-02-14 183
9684ec186f8fad Ard Biesheuvel 2024-02-14 184 create_init_idmap(init_idmap_pg_dir, mask);
9684ec186f8fad Ard Biesheuvel 2024-02-14 185 dsb(ishst);
9684ec186f8fad Ard Biesheuvel 2024-02-14 186
9684ec186f8fad Ard Biesheuvel 2024-02-14 187 /* switch back to the updated initial ID map */
9684ec186f8fad Ard Biesheuvel 2024-02-14 188 set_ttbr0_for_lpa2((u64)init_idmap_pg_dir);
9684ec186f8fad Ard Biesheuvel 2024-02-14 189
9684ec186f8fad Ard Biesheuvel 2024-02-14 190 /* wipe the temporary ID map from memory */
9684ec186f8fad Ard Biesheuvel 2024-02-14 @191 memset(init_pg_dir, 0, (u64)init_pg_end - (u64)init_pg_dir);
9684ec186f8fad Ard Biesheuvel 2024-02-14 192 }
9684ec186f8fad Ard Biesheuvel 2024-02-14 193
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Ard,
kernel test robot noticed the following build errors:
[auto build test ERROR on soc/for-next]
[also build test ERROR on linus/master v6.15-rc5 next-20250505]
[cannot apply to arm64/for-next/core kvmarm/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Ard-Biesheuvel/arm64-boot-Move-init_pgdir-into-__pi_-namespace/20250503-192534
base: https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
patch link: https://lore.kernel.org/r/20250503112137.1962910-6-ardb%2Bgit%40google.com
patch subject: [PATCH 1/3] arm64/boot: Move init_pgdir[] into __pi_ namespace
config: arm64-randconfig-001-20250505 (https://download.01.org/0day-ci/archive/20250505/202505052102.U2NQHrS4-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250505/202505052102.U2NQHrS4-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505052102.U2NQHrS4-lkp@intel.com/
All errors (new ones prefixed by >>):
>> arch/arm64/kernel/pi/map_kernel.c:191:30: error: use of undeclared identifier 'init_pg_end'
191 | memset(init_pg_dir, 0, (u64)init_pg_end - (u64)init_pg_dir);
| ^
arch/arm64/kernel/pi/map_kernel.c:222:30: error: use of undeclared identifier 'init_pg_end'
222 | memset(__bss_start, 0, (u64)init_pg_end - (u64)__bss_start);
| ^
2 errors generated.
vim +/init_pg_end +191 arch/arm64/kernel/pi/map_kernel.c
9684ec186f8fadd Ard Biesheuvel 2024-02-14 158
9684ec186f8fadd Ard Biesheuvel 2024-02-14 159 static void __init remap_idmap_for_lpa2(void)
9684ec186f8fadd Ard Biesheuvel 2024-02-14 160 {
9684ec186f8fadd Ard Biesheuvel 2024-02-14 161 /* clear the bits that change meaning once LPA2 is turned on */
9684ec186f8fadd Ard Biesheuvel 2024-02-14 162 pteval_t mask = PTE_SHARED;
9684ec186f8fadd Ard Biesheuvel 2024-02-14 163
9684ec186f8fadd Ard Biesheuvel 2024-02-14 164 /*
9684ec186f8fadd Ard Biesheuvel 2024-02-14 165 * We have to clear bits [9:8] in all block or page descriptors in the
9684ec186f8fadd Ard Biesheuvel 2024-02-14 166 * initial ID map, as otherwise they will be (mis)interpreted as
9684ec186f8fadd Ard Biesheuvel 2024-02-14 167 * physical address bits once we flick the LPA2 switch (TCR.DS). Since
9684ec186f8fadd Ard Biesheuvel 2024-02-14 168 * we cannot manipulate live descriptors in that way without creating
9684ec186f8fadd Ard Biesheuvel 2024-02-14 169 * potential TLB conflicts, let's create another temporary ID map in a
9684ec186f8fadd Ard Biesheuvel 2024-02-14 170 * LPA2 compatible fashion, and update the initial ID map while running
9684ec186f8fadd Ard Biesheuvel 2024-02-14 171 * from that.
9684ec186f8fadd Ard Biesheuvel 2024-02-14 172 */
9684ec186f8fadd Ard Biesheuvel 2024-02-14 173 create_init_idmap(init_pg_dir, mask);
9684ec186f8fadd Ard Biesheuvel 2024-02-14 174 dsb(ishst);
9684ec186f8fadd Ard Biesheuvel 2024-02-14 175 set_ttbr0_for_lpa2((u64)init_pg_dir);
9684ec186f8fadd Ard Biesheuvel 2024-02-14 176
9684ec186f8fadd Ard Biesheuvel 2024-02-14 177 /*
9684ec186f8fadd Ard Biesheuvel 2024-02-14 178 * Recreate the initial ID map with the same granularity as before.
9684ec186f8fadd Ard Biesheuvel 2024-02-14 179 * Don't bother with the FDT, we no longer need it after this.
9684ec186f8fadd Ard Biesheuvel 2024-02-14 180 */
9684ec186f8fadd Ard Biesheuvel 2024-02-14 181 memset(init_idmap_pg_dir, 0,
ecc54006f158ae0 Zenghui Yu 2024-06-21 182 (u64)init_idmap_pg_end - (u64)init_idmap_pg_dir);
9684ec186f8fadd Ard Biesheuvel 2024-02-14 183
9684ec186f8fadd Ard Biesheuvel 2024-02-14 184 create_init_idmap(init_idmap_pg_dir, mask);
9684ec186f8fadd Ard Biesheuvel 2024-02-14 185 dsb(ishst);
9684ec186f8fadd Ard Biesheuvel 2024-02-14 186
9684ec186f8fadd Ard Biesheuvel 2024-02-14 187 /* switch back to the updated initial ID map */
9684ec186f8fadd Ard Biesheuvel 2024-02-14 188 set_ttbr0_for_lpa2((u64)init_idmap_pg_dir);
9684ec186f8fadd Ard Biesheuvel 2024-02-14 189
9684ec186f8fadd Ard Biesheuvel 2024-02-14 190 /* wipe the temporary ID map from memory */
9684ec186f8fadd Ard Biesheuvel 2024-02-14 @191 memset(init_pg_dir, 0, (u64)init_pg_end - (u64)init_pg_dir);
9684ec186f8fadd Ard Biesheuvel 2024-02-14 192 }
9684ec186f8fadd Ard Biesheuvel 2024-02-14 193
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Sat, 3 May 2025 at 13:22, Ard Biesheuvel <ardb+git@google.com> wrote:
>
> From: Ard Biesheuvel <ardb@kernel.org>
>
> init_pgdir[] is only referenced from the startup code, but lives after
> BSS in the linker map. Before tightening the rules about accessing BSS
> from startup code, move init_pgdir[] into the __pi_ namespace, so it
> does not need to be exported explicitly.
>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
> arch/arm64/include/asm/pgtable.h | 2 --
> arch/arm64/kernel/image-vars.h | 2 --
> arch/arm64/kernel/pi/pi.h | 1 +
> arch/arm64/kernel/vmlinux.lds.S | 4 ++--
> 4 files changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index d3b538be1500..6a040f0bbfe1 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -754,8 +754,6 @@ static inline bool pud_table(pud_t pud) { return true; }
> PUD_TYPE_TABLE)
> #endif
>
> -extern pgd_t init_pg_dir[];
> -extern pgd_t init_pg_end[];
> extern pgd_t swapper_pg_dir[];
> extern pgd_t idmap_pg_dir[];
> extern pgd_t tramp_pg_dir[];
> diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
> index 5e3c4b58f279..a0977f7cd3ec 100644
> --- a/arch/arm64/kernel/image-vars.h
> +++ b/arch/arm64/kernel/image-vars.h
> @@ -56,8 +56,6 @@ PROVIDE(__pi_memstart_offset_seed = memstart_offset_seed);
>
> PROVIDE(__pi_init_idmap_pg_dir = init_idmap_pg_dir);
> PROVIDE(__pi_init_idmap_pg_end = init_idmap_pg_end);
> -PROVIDE(__pi_init_pg_dir = init_pg_dir);
> -PROVIDE(__pi_init_pg_end = init_pg_end);
> PROVIDE(__pi_swapper_pg_dir = swapper_pg_dir);
>
> PROVIDE(__pi__text = _text);
> diff --git a/arch/arm64/kernel/pi/pi.h b/arch/arm64/kernel/pi/pi.h
> index c91e5e965cd3..38a908d048e8 100644
> --- a/arch/arm64/kernel/pi/pi.h
> +++ b/arch/arm64/kernel/pi/pi.h
> @@ -22,6 +22,7 @@ static inline void *prel64_to_pointer(const prel64_t *offset)
> extern bool dynamic_scs_is_enabled;
>
> extern pgd_t init_idmap_pg_dir[], init_idmap_pg_end[];
> +extern pgd_t init_pg_dir[];
>
Apologies, I hit send too quickly - init_pg_end[] is missing here.
© 2016 - 2026 Red Hat, Inc.