Booting an LPAE-enabled kernel built with CONFIG_CC_OPTIMIZE_FOR_SIZE=y
fails when starting userspace:
Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
CPU: 1 PID: 1 Comm: init Tainted: G W N 6.9.0-rc1-koelsch-00004-g7af5b901e847 #1930
Hardware name: Generic R-Car Gen2 (Flattened Device Tree)
Call trace:
unwind_backtrace from show_stack+0x10/0x14
show_stack from dump_stack_lvl+0x78/0xa8
dump_stack_lvl from panic+0x118/0x398
panic from do_exit+0x1ec/0x938
do_exit from sys_exit_group+0x0/0x10
---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004 ]---
Add the missing memory clobber to cpu_set_ttbcr(), as suggested by
Russell King.
Force inlining of uaccess_save_and_enable(), as suggested by Ard
Biesheuvel.
The latter fixes booting on Koelsch.
Fixes: 7af5b901e84743c6 ("ARM: 9358/2: Implement PAN for LPAE by TTBR0 page table walks disablement")
Closes: https://lore.kernel.org/r/CAMuHMdWTAJcZ9BReWNhpmsgkOzQxLNb5OhNYxzxv6D5TSh2fwQ@xxxxxxxxxxxxxx/
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
Feel free to fold into the original commit.
Apparently the "From: Catalin Marinas <catalin.marinas@xxxxxxx>" in
https://lore.kernel.org/r/20240312-arm32-lpae-pan-v3-4-532647afcd38@xxxxxxxxxx
is not reflected in commit 7af5b901e84743c6?
---
arch/arm/include/asm/proc-fns.h | 2 +-
arch/arm/include/asm/uaccess.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index 9b3105a2a5e0691e..b4986a23d8528a50 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -187,7 +187,7 @@ static inline unsigned int cpu_get_ttbcr(void)
static inline void cpu_set_ttbcr(unsigned int ttbcr)
{
- asm("mcr p15, 0, %0, c2, c0, 2" : : "r" (ttbcr));
+ asm volatile("mcr p15, 0, %0, c2, c0, 2" : : "r" (ttbcr) : "memory");
}
#else /*!CONFIG_MMU */
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 25d21d7d6e3efee0..6c9c16d767cfd5df 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -47,7 +47,7 @@ static __always_inline void uaccess_restore(unsigned int flags)
#elif defined(CONFIG_CPU_TTBR0_PAN)
-static inline unsigned int uaccess_save_and_enable(void)
+static __always_inline unsigned int uaccess_save_and_enable(void)
{
unsigned int old_ttbcr = cpu_get_ttbcr();
--
2.34.1
