diff options
| author | Christophe Leroy <[email protected]> | 2024-09-06 10:33:43 +0200 |
|---|---|---|
| committer | Jason A. Donenfeld <[email protected]> | 2024-09-13 17:28:36 +0200 |
| commit | c73049389e58c01e2e3bbfae900c8daeee177191 (patch) | |
| tree | bac26c60c30c643cba8c970b77972ce4cfedfa8c /arch/powerpc/include/asm/vdso_datapage.h | |
| parent | 8bc7c5e525584903ea83332e18a2118ed3b1985e (diff) | |
powerpc/vdso: Fix VDSO data access when running in a non-root time namespace
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 <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Christophe Leroy <[email protected]>
Acked-by: Michael Ellerman <[email protected]>
Signed-off-by: Jason A. Donenfeld <[email protected]>
Diffstat (limited to 'arch/powerpc/include/asm/vdso_datapage.h')
| -rw-r--r-- | arch/powerpc/include/asm/vdso_datapage.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h index a585c8e538ff..939daf6b695e 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__ */ |