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tile: implement gettimeofday() via vDSO

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This change creates the framework for vDSO calls, makes the existing
rt_sigreturn() mechanism use it, and adds a fast gettimeofday().
Now that we need to expose the vDSO address to userspace, we add
AT_SYSINFO_EHDR to the set of aux entries provided to userspace.
(You can disable any extra vDSO support by booting with vdso=0,
but the rt_sigreturn vDSO page will still be provided.)

Note that glibc has supported the tile vDSO since release 2.17.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This commit is contained in:
Chris Metcalf
2013-08-07 15:33:32 -04:00
parent 0c1d1917c5
commit 4a556f4f56
22 changed files with 732 additions and 62 deletions
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8
arch/tile/include/asm/page.h
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@@ -38,6 +38,12 @@
#define PAGE_MASK (~(PAGE_SIZE - 1))
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
/*
* We do define AT_SYSINFO_EHDR to support vDSO,
* but don't use the gate mechanism.
*/
#define __HAVE_ARCH_GATE_AREA 1
/*
* If the Kconfig doesn't specify, set a maximum zone order that
* is enough so that we can create huge pages from small pages given
@@ -246,7 +252,7 @@ static inline __attribute_const__ int get_order(unsigned long size)
#endif /* __tilegx__ */
#ifndef __ASSEMBLY__
#if !defined(__ASSEMBLY__) && !defined(VDSO_BUILD)
#ifdef CONFIG_HIGHMEM