Benjamin Herrenschmidt <b...@kernel.crashing.org> writes:
> Maybe a better fix is to force alignment in the kernel by requesting
> size + 64k - 4k and aligning it.
Sure you are right.
Andreas.
>From b9441a3d2148d439e2730def3222a7b70dccc432 Mon Sep 17 00:00:00 2001
From: Andreas Schwab <sch...@linux-m68k.org>
Date: Sun, 4 Oct 2009 14:29:04 +0200
Subject: [PATCH] powerpc: align vDSO base address
Signed-off-by: Andreas Schwab <sch...@linux-m68k.org>
---
arch/powerpc/kernel/vdso.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 94e2df3..137dc22 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -50,6 +50,9 @@
/* Max supported size for symbol names */
#define MAX_SYMNAME 64
+/* The alignment of the vDSO */
+#define VDSO_ALIGNMENT (1 << 16)
+
extern char vdso32_start, vdso32_end;
static void *vdso32_kbase = &vdso32_start;
static unsigned int vdso32_pages;
@@ -231,15 +234,21 @@ int arch_setup_additional_pages(struct linux_binprm
*bprm, int uses_interp)
* pick a base address for the vDSO in process space. We try to put it
* at vdso_base which is the "natural" base for it, but we might fail
* and end up putting it elsewhere.
+ * Add enough to the size so that the result can be aligned.
*/
down_write(&mm->mmap_sem);
vdso_base = get_unmapped_area(NULL, vdso_base,
- vdso_pages << PAGE_SHIFT, 0, 0);
+ (vdso_pages << PAGE_SHIFT) +
+ ((VDSO_ALIGNMENT - 1) & PAGE_MASK),
+ 0, 0);
if (IS_ERR_VALUE(vdso_base)) {
rc = vdso_base;
goto fail_mmapsem;
}
+ /* Add required alignment. */
+ vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
+
/*
* Put vDSO base into mm struct. We need to do this before calling
* install_special_mapping or the perf counter mmap tracking code
--
1.6.4.4
--
Andreas Schwab, sch...@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
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