arm64: Rename page table BSS section to .bss..pgtbl

Rename the .pgdir.bss section to .bss..pgtbl so that the compiler will
notice the leading ".bss" and mark it as NOBITS by default (rather than
PROGBITS, which would take up space in Image binary, forcing all of the
preceding BSS to be emitted into the image as well). This supersedes the
NOLOAD linker directive, which achieves the same thing, and can be
therefore be dropped.

Also, rename .pgdir to .pgtbl to be more generic, as page tables of
various levels will reside here.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/include/asm/linkage.h b/arch/arm64/include/asm/linkage.h
index 40bd17add53973410ed1979c84ff1c0c22aeecde..8637f667667c1a20a2a89802f546e0a7feface84 100644 (file)
--- a/arch/arm64/include/asm/linkage.h
+++ b/arch/arm64/include/asm/linkage.h
@@ -43,4 +43,6 @@
        SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)        \
        bti c ;
 
+#define __bss_pgtbl __section(".bss..pgtbl") __aligned(PAGE_SIZE)
+
 #endif

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index fb95754f28760b6d4512eacfbde1b9a72a871d79..5e1211c540ab23033101b004f497391c13f5de2b 100644 (file)
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -13,8 +13,6 @@
 
 #ifndef __ASSEMBLER__
 
-#define __pgtbl_bss __section(".pgdir.bss") __aligned(PAGE_SIZE)
-
 #include <linux/refcount.h>
 #include <asm/cpufeature.h>
 

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 2b0ebfb30c63e17edc74315e023af39eb676f5c2..d3ed59abab3812d89b8a3b9ff10c2dfb5948d920 100644 (file)
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -352,11 +352,11 @@ SECTIONS
        BSS_SECTION(SBSS_ALIGN, 0, PAGE_SIZE)
        __pi___bss_start = __bss_start;
 
-       /* fixmap BSS starts here - preceding data/BSS is omitted from the linear map */
-       .pgdir.bss (NOLOAD) : ALIGN(PAGE_SIZE) {
-               *(.pgdir.bss)
+       /* page table BSS starts here - preceding data/BSS is omitted from the linear map */
+       .pgtbl : ALIGN(PAGE_SIZE) {
+               *(.bss..pgtbl)
        }
-       ASSERT(ADDR(.pgdir.bss) == __bss_stop, ".pgdir.bss must follow BSS")
+       ASSERT(ADDR(.pgtbl) == __bss_stop, ".pgtbl must follow BSS")
 
        . = ALIGN(PAGE_SIZE);
        __pi_init_pg_dir = .;

diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c
index 1a3bbd67dd762155af852fe6f4658b049f7892ba..f66a0016dd02dfa777cda026c3accb476bfdeb86 100644 (file)
--- a/arch/arm64/mm/fixmap.c
+++ b/arch/arm64/mm/fixmap.c
@@ -31,9 +31,9 @@ static_assert(NR_BM_PMD_TABLES == 1);
 
 #define BM_PTE_TABLE_IDX(addr) __BM_TABLE_IDX(addr, PMD_SHIFT)
 
-static pte_t bm_pte[NR_BM_PTE_TABLES][PTRS_PER_PTE] __pgtbl_bss;
-static pmd_t bm_pmd[PTRS_PER_PMD] __pgtbl_bss __maybe_unused;
-static pud_t bm_pud[PTRS_PER_PUD] __pgtbl_bss __maybe_unused;
+static pte_t bm_pte[NR_BM_PTE_TABLES][PTRS_PER_PTE] __bss_pgtbl;
+static pmd_t bm_pmd[PTRS_PER_PMD] __bss_pgtbl __maybe_unused;
+static pud_t bm_pud[PTRS_PER_PUD] __bss_pgtbl __maybe_unused;
 
 static inline pte_t *fixmap_pte(unsigned long addr)
 {

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index dbf22cae82ee0fe74136fc115b82ece107f8c5b0..3fcad956fdf7cb31b924ccee6f2c42612c707458 100644 (file)
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -214,7 +214,7 @@ asmlinkage void __init kasan_early_init(void)
                 * shadow pud_t[]/p4d_t[], which could end up getting corrupted
                 * when the linear region is mapped.
                 */
-               static pte_t tbl[PTRS_PER_PTE] __pgtbl_bss;
+               static pte_t tbl[PTRS_PER_PTE] __bss_pgtbl;
                pgd_t *pgdp = pgd_offset_k(KASAN_SHADOW_START);
 
                set_pgd(pgdp, __pgd(__pa_symbol(tbl) | PGD_TYPE_TABLE));