diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2025-09-09 12:03:49 +0200 |
|---|---|---|
| committer | Madhavan Srinivasan <maddy@linux.ibm.com> | 2025-09-16 16:16:00 +0530 |
| commit | 9316512b717f6f25c4649b3fdb0a905b6a318e9f (patch) | |
| tree | 4fbbab2694704e213657717f8d462bd5e98a24a2 /arch/powerpc/include | |
| parent | 7cec88bfdd33434d62d4d5ba664127fa175b50e7 (diff) | |
powerpc/32: Remove PAGE_KERNEL_TEXT to fix startup failure
PAGE_KERNEL_TEXT is an old macro that is used to tell kernel whether
kernel text has to be mapped read-only or read-write based on build
time options.
But nowadays, with functionnalities like jump_labels, static links,
etc ... more only less all kernels need to be read-write at some
point, and some combinations of configs failed to work due to
innacurate setting of PAGE_KERNEL_TEXT. On the other hand, today
we have CONFIG_STRICT_KERNEL_RWX which implements a more controlled
access to kernel modifications.
Instead of trying to keep PAGE_KERNEL_TEXT accurate with all
possible options that may imply kernel text modification, always
set kernel text read-write at startup and rely on
CONFIG_STRICT_KERNEL_RWX to provide accurate protection.
Do this by passing PAGE_KERNEL_X to map_kernel_page() in
__maping_ram_chunk() instead of passing PAGE_KERNEL_TEXT. Once
this is done, the only remaining user of PAGE_KERNEL_TEXT is
mmu_mark_initmem_nx() which uses it in a call to setibat().
As setibat() ignores the RW/RO, we can seamlessly replace
PAGE_KERNEL_TEXT by PAGE_KERNEL_X here as well and get rid of
PAGE_KERNEL_TEXT completely.
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Closes: https://lore.kernel.org/all/342b4120-911c-4723-82ec-d8c9b03a8aef@mailbox.org/
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/8e2d793abf87ae3efb8f6dce10f974ac0eda61b8.1757412205.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/pgtable.h | 12 |
1 files changed, 0 insertions, 12 deletions
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index fd29fb289d1e..17fd7ff6e535 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -20,18 +20,6 @@ struct mm_struct; #include <asm/nohash/pgtable.h> #endif /* !CONFIG_PPC_BOOK3S */ -/* - * Protection used for kernel text. We want the debuggers to be able to - * set breakpoints anywhere, so don't write protect the kernel text - * on platforms where such control is possible. - */ -#if defined(CONFIG_KGDB) || defined(CONFIG_XMON) || defined(CONFIG_BDI_SWITCH) || \ - defined(CONFIG_KPROBES) || defined(CONFIG_DYNAMIC_FTRACE) -#define PAGE_KERNEL_TEXT PAGE_KERNEL_X -#else -#define PAGE_KERNEL_TEXT PAGE_KERNEL_ROX -#endif - /* Make modules code happy. We don't set RO yet */ #define PAGE_KERNEL_EXEC PAGE_KERNEL_X |