6.6-stable review patch. If anyone has any objections, please let me know.
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From: Christophe Leroy christophe.leroy@csgroup.eu
[ Upstream commit c73049389e58c01e2e3bbfae900c8daeee177191 ]
When running in a non-root time namespace, the global VDSO data page is replaced by a dedicated namespace data page and the global data page is mapped next to it. Detailed explanations can be found at commit 660fd04f9317 ("lib/vdso: Prepare for time namespace support").
When it happens, __kernel_get_syscall_map and __kernel_get_tbfreq and __kernel_sync_dicache don't work anymore because they read 0 instead of the data they need.
To address that, clock_mode has to be read. When it is set to VDSO_CLOCKMODE_TIMENS, it means it is a dedicated namespace data page and the global data is located on the following page.
Add a macro called get_realdatapage which reads clock_mode and add PAGE_SIZE to the pointer provided by get_datapage macro when clock_mode is equal to VDSO_CLOCKMODE_TIMENS. Use this new macro instead of get_datapage macro except for time functions as they handle it internally.
Fixes: 74205b3fc2ef ("powerpc/vdso: Add support for time namespaces") Reported-by: Jason A. Donenfeld Jason@zx2c4.com Closes: https://lore.kernel.org/all/ZtnYqZI-nrsNslwy@zx2c4.com/ Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu Acked-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/include/asm/vdso_datapage.h | 15 +++++++++++++++ arch/powerpc/kernel/asm-offsets.c | 2 ++ arch/powerpc/kernel/vdso/cacheflush.S | 2 +- arch/powerpc/kernel/vdso/datapage.S | 4 ++-- 4 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h index a585c8e538ff0..939daf6b695ef 100644 --- a/arch/powerpc/include/asm/vdso_datapage.h +++ b/arch/powerpc/include/asm/vdso_datapage.h @@ -111,6 +111,21 @@ extern struct vdso_arch_data *vdso_data; addi \ptr, \ptr, (_vdso_datapage - 999b)@l .endm
+#include <asm/asm-offsets.h> +#include <asm/page.h> + +.macro get_realdatapage ptr scratch + get_datapage \ptr +#ifdef CONFIG_TIME_NS + lwz \scratch, VDSO_CLOCKMODE_OFFSET(\ptr) + xoris \scratch, \scratch, VDSO_CLOCKMODE_TIMENS@h + xori \scratch, \scratch, VDSO_CLOCKMODE_TIMENS@l + cntlzw \scratch, \scratch + rlwinm \scratch, \scratch, PAGE_SHIFT - 5, 1 << PAGE_SHIFT + add \ptr, \ptr, \scratch +#endif +.endm + #endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 9f14d95b8b32f..2affd30468bc4 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -348,6 +348,8 @@ int main(void) #else OFFSET(CFG_SYSCALL_MAP32, vdso_arch_data, syscall_map); #endif + OFFSET(VDSO_CLOCKMODE_OFFSET, vdso_arch_data, data[0].clock_mode); + DEFINE(VDSO_CLOCKMODE_TIMENS, VDSO_CLOCKMODE_TIMENS);
#ifdef CONFIG_BUG DEFINE(BUG_ENTRY_SIZE, sizeof(struct bug_entry)); diff --git a/arch/powerpc/kernel/vdso/cacheflush.S b/arch/powerpc/kernel/vdso/cacheflush.S index 0085ae464dac9..3b2479bd2f9a1 100644 --- a/arch/powerpc/kernel/vdso/cacheflush.S +++ b/arch/powerpc/kernel/vdso/cacheflush.S @@ -30,7 +30,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE) #ifdef CONFIG_PPC64 mflr r12 .cfi_register lr,r12 - get_datapage r10 + get_realdatapage r10, r11 mtlr r12 .cfi_restore lr #endif diff --git a/arch/powerpc/kernel/vdso/datapage.S b/arch/powerpc/kernel/vdso/datapage.S index db8e167f01667..2b19b6201a33a 100644 --- a/arch/powerpc/kernel/vdso/datapage.S +++ b/arch/powerpc/kernel/vdso/datapage.S @@ -28,7 +28,7 @@ V_FUNCTION_BEGIN(__kernel_get_syscall_map) mflr r12 .cfi_register lr,r12 mr. r4,r3 - get_datapage r3 + get_realdatapage r3, r11 mtlr r12 #ifdef __powerpc64__ addi r3,r3,CFG_SYSCALL_MAP64 @@ -52,7 +52,7 @@ V_FUNCTION_BEGIN(__kernel_get_tbfreq) .cfi_startproc mflr r12 .cfi_register lr,r12 - get_datapage r3 + get_realdatapage r3, r11 #ifndef __powerpc64__ lwz r4,(CFG_TB_TICKS_PER_SEC + 4)(r3) #endif