This is a note to let you know that I've just added the patch titled powerpc/vmlinux.lds: Add an explicit symbol for the SRWX boundary to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-vmlinux.lds-add-an-explicit-symbol-for-the-s.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit f7674516e7c87e7435f4f4a4f9178c8bbb84f0d4 Author: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Date: Fri Sep 16 14:41:24 2022 +1000 powerpc/vmlinux.lds: Add an explicit symbol for the SRWX boundary [ Upstream commit b150a4d12b919baf956b807aa305cf78df03d0fe ] Currently __init_begin is used as the boundary for strict RWX between executable/read-only text and data, and non-executable (after boot) code and data. But that's a little subtle, so add an explicit symbol to document that the SRWX boundary lies there, and add a comment making it clear that __init_begin must also begin there. Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220916131422.318752-2-mpe@xxxxxxxxxxxxxx Stable-dep-of: 111bcb373853 ("powerpc/64s/radix: Fix RWX mapping with relocated kernel") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h index 79cb7a25a5fb6..e92d39c0cd1d9 100644 --- a/arch/powerpc/include/asm/sections.h +++ b/arch/powerpc/include/asm/sections.h @@ -9,6 +9,7 @@ #include <asm-generic/sections.h> extern char __head_end[]; +extern char __srwx_boundary[]; #ifdef __powerpc64__ diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index bcbe41c6998ca..a664d0c4344a9 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -208,11 +208,16 @@ SECTIONS } #endif + /* + * Various code relies on __init_begin being at the strict RWX boundary. + */ + . = ALIGN(STRICT_ALIGN_SIZE); + __srwx_boundary = .; + __init_begin = .; + /* * Init sections discarded at runtime */ - . = ALIGN(STRICT_ALIGN_SIZE); - __init_begin = .; .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) { _sinittext = .; INIT_TEXT diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c index bfca0afe91126..692c336e4f55b 100644 --- a/arch/powerpc/mm/book3s32/mmu.c +++ b/arch/powerpc/mm/book3s32/mmu.c @@ -159,7 +159,7 @@ static unsigned long __init __mmu_mapin_ram(unsigned long base, unsigned long to unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) { unsigned long done; - unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET; + unsigned long border = (unsigned long)__srwx_boundary - PAGE_OFFSET; unsigned long size; size = roundup_pow_of_two((unsigned long)_einittext - PAGE_OFFSET); diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c index a339cb5de5dd1..52e27fd995da7 100644 --- a/arch/powerpc/mm/book3s64/radix_pgtable.c +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -260,8 +260,8 @@ print_mapping(unsigned long start, unsigned long end, unsigned long size, bool e static unsigned long next_boundary(unsigned long addr, unsigned long end) { #ifdef CONFIG_STRICT_KERNEL_RWX - if (addr < __pa_symbol(__init_begin)) - return __pa_symbol(__init_begin); + if (addr < __pa_symbol(__srwx_boundary)) + return __pa_symbol(__srwx_boundary); #endif return end; }