forked from luck/tmp_suning_uos_patched
4763ed4d45
The 32- and 64-bit code used very different mechanisms for enabling NX, but even the 32-bit code was enabling NX in head_32.S if it is available. Furthermore, we had a bewildering collection of tests for the available of NX. This patch: a) merges the 32-bit set_nx() and the 64-bit check_efer() function into a single x86_configure_nx() function. EFER control is left to the head code. b) eliminates the nx_enabled variable entirely. Things that need to test for NX enablement can verify __supported_pte_mask directly, and cpu_has_nx gives the supported status of NX. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Tejun Heo <tj@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Vegard Nossum <vegardno@ifi.uio.no> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Chris Wright <chrisw@sous-sol.org> LKML-Reference: <1258154897-6770-5-git-send-email-hpa@zytor.com> Acked-by: Kees Cook <kees.cook@canonical.com>
39 lines
691 B
C
39 lines
691 B
C
#include <linux/spinlock.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <asm/pgtable.h>
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#include <asm/proto.h>
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static int disable_nx __cpuinitdata;
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/*
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* noexec = on|off
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*
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* Control non-executable mappings for processes.
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*
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* on Enable
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* off Disable
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*/
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static int __init noexec_setup(char *str)
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{
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if (!str)
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return -EINVAL;
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if (!strncmp(str, "on", 2)) {
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disable_nx = 0;
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} else if (!strncmp(str, "off", 3)) {
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disable_nx = 1;
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}
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x86_configure_nx();
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return 0;
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}
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early_param("noexec", noexec_setup);
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void __cpuinit x86_configure_nx(void)
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{
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if (cpu_has_nx && !disable_nx)
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__supported_pte_mask |= _PAGE_NX;
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else
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__supported_pte_mask &= ~_PAGE_NX;
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}
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