* [PATCH] x86/boot/64: Fix missed fixup_pointer() for next_early_pgt access
@ 2019-06-20 11:24 Kirill A. Shutemov
2019-06-26 5:29 ` [tip:x86/urgent] x86/boot/64: Add missing " tip-bot for Kirill A. Shutemov
0 siblings, 1 reply; 2+ messages in thread
From: Kirill A. Shutemov @ 2019-06-20 11:24 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
Dave Hansen, Andy Lutomirski, Peter Zijlstra
Cc: x86, linux-kernel, Kirill A. Shutemov, Alexander Potapenko
__startup_64() uses fixup_pointer() to access global variables in a
position-independent fashion. Access to next_early_pgt was wrapped into
the helper, but one of the instance in 5-level paging branch was missed.
GCC generates a R_X86_64_PC32 PC-relative relocation for the access
which doesn't trigger the issue, but Clang emmits a R_X86_64_32S which
leads to an invalid memory and system reboot.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: 187e91fe5e91 ("x86/boot/64/clang: Use fixup_pointer() to access 'next_early_pgt'")
Cc: Alexander Potapenko <glider@google.com>
---
arch/x86/kernel/head64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 16b1cbd3a61e..4d98ba8063d1 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -184,7 +184,7 @@ unsigned long __head __startup_64(unsigned long physaddr,
pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
if (la57) {
- p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
+ p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [tip:x86/urgent] x86/boot/64: Add missing fixup_pointer() for next_early_pgt access
2019-06-20 11:24 [PATCH] x86/boot/64: Fix missed fixup_pointer() for next_early_pgt access Kirill A. Shutemov
@ 2019-06-26 5:29 ` tip-bot for Kirill A. Shutemov
0 siblings, 0 replies; 2+ messages in thread
From: tip-bot for Kirill A. Shutemov @ 2019-06-26 5:29 UTC (permalink / raw)
To: linux-tip-commits
Cc: kirill.shutemov, linux-kernel, mingo, peterz, kirill, luto, tglx,
hpa, glider, dave.hansen, bp
Commit-ID: c1887159eb48ba40e775584cfb2a443962cf1a05
Gitweb: https://git.kernel.org/tip/c1887159eb48ba40e775584cfb2a443962cf1a05
Author: Kirill A. Shutemov <kirill@shutemov.name>
AuthorDate: Thu, 20 Jun 2019 14:24:22 +0300
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 26 Jun 2019 07:25:09 +0200
x86/boot/64: Add missing fixup_pointer() for next_early_pgt access
__startup_64() uses fixup_pointer() to access global variables in a
position-independent fashion. Access to next_early_pgt was wrapped into the
helper, but one instance in the 5-level paging branch was missed.
GCC generates a R_X86_64_PC32 PC-relative relocation for the access which
doesn't trigger the issue, but Clang emmits a R_X86_64_32S which leads to
an invalid memory access and system reboot.
Fixes: 187e91fe5e91 ("x86/boot/64/clang: Use fixup_pointer() to access 'next_early_pgt'")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Potapenko <glider@google.com>
Link: https://lkml.kernel.org/r/20190620112422.29264-1-kirill.shutemov@linux.intel.com
---
arch/x86/kernel/head64.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 7df5bce4e1be..29ffa495bd1c 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -184,7 +184,8 @@ unsigned long __head __startup_64(unsigned long physaddr,
pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
if (la57) {
- p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
+ p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
+ physaddr);
i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
^ permalink raw reply related [flat|nested] 2+ messages in thread
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