Commit 45a1b8cc authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'x86_misc_for_7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull misc x86 updates from Dave Hansen:
 "The usual smattering of x86/misc changes.

  The IPv6 patch in here surprised me in a couple of ways. First, the
  function it inlines is able to eat a lot more CPU time than I would
  have expected. Second, the inlining does not seem to bloat the kernel,
  at least in the configs folks have tested.

   - Inline x86-specific IPv6 checksum helper

   - Update IOMMU docs to use stable identifiers

   - Print unhashed pointers on fatal stack overflows"

* tag 'x86_misc_for_7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/traps: Print unhashed pointers on stack overflow
  Documentation/x86: Update IOMMU spec references to use stable identifiers
  x86/lib: Inline csum_ipv6_magic()
parents 6f7e6393 6b32c935

Documentation/arch/x86/iommu.rst

+4 −3
Original line number Diff line number Diff line
@@ -2,10 +2,11 @@ 
x86 IOMMU Support

=================



The architecture specs can be obtained from the below locations.

The architecture specs can be obtained from the vendor websites.

Search for the following documents to obtain the latest versions:



- Intel: http://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/vt-directed-io-spec.pdf

- AMD: https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/specifications/48882_3_07_PUB.pdf

- Intel: Intel Virtualization Technology for Directed I/O Architecture Specification (ID: D51397)

- AMD: AMD I/O Virtualization Technology (IOMMU) Specification (ID: 48882)



This guide gives a quick cheat sheet for some basic understanding.

arch/x86/include/asm/checksum_64.h

+33 −12
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
 */



#include <linux/compiler.h>

#include <linux/in6.h>

#include <asm/byteorder.h>



/**
@@ -145,6 +146,17 @@ extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len); 
 */

extern __sum16 ip_compute_csum(const void *buff, int len);



static inline unsigned add32_with_carry(unsigned a, unsigned b)

{

	asm("addl %2,%0\n\t"

	    "adcl $0,%0"

	    : "=r" (a)

	    : "0" (a), "rm" (b));

	return a;

}



#define _HAVE_ARCH_IPV6_CSUM 1



/**

 * csum_ipv6_magic - Compute checksum of an IPv6 pseudo header.

 * @saddr: source address
@@ -158,20 +170,29 @@ extern __sum16 ip_compute_csum(const void *buff, int len); 
 * Returns the unfolded 32bit checksum.

 */



struct in6_addr;

static inline __sum16 csum_ipv6_magic(

	const struct in6_addr *_saddr, const struct in6_addr *_daddr,

	__u32 len, __u8 proto, __wsum sum)

{

	const unsigned long *saddr = (const unsigned long *)_saddr;

	const unsigned long *daddr = (const unsigned long *)_daddr;

	__u64 sum64;



#define _HAVE_ARCH_IPV6_CSUM 1

extern __sum16

csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,

		__u32 len, __u8 proto, __wsum sum);

	sum64 = (__force __u64)htonl(len) + (__force __u64)htons(proto) +

		(__force __u64)sum;



static inline unsigned add32_with_carry(unsigned a, unsigned b)

{

	asm("addl %2,%0\n\t"

	    "adcl $0,%0"

	    : "=r" (a)

	    : "0" (a), "rm" (b));

	return a;

	asm("	addq %1,%[sum64]\n"

	    "	adcq %2,%[sum64]\n"

	    "	adcq %3,%[sum64]\n"

	    "	adcq %4,%[sum64]\n"

	    "	adcq $0,%[sum64]\n"



	    : [sum64] "+r" (sum64)

	    : "m" (saddr[0]), "m" (saddr[1]),

	      "m" (daddr[0]), "m" (daddr[1]));



	return csum_fold(

	       (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));

}



#define HAVE_ARCH_CSUM_ADD

arch/x86/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -549,7 +549,7 @@ __visible void __noreturn handle_stack_overflow(struct pt_regs *regs, 
{

	const char *name = stack_type_name(info->type);



	printk(KERN_EMERG "BUG: %s stack guard page was hit at %p (stack is %p..%p)\n",

	printk(KERN_EMERG "BUG: %s stack guard page was hit at %px (stack is %px..%px)\n",

	       name, (void *)fault_address, info->begin, info->end);



	die("stack guard page", regs, 0);

arch/x86/lib/csum-wrappers_64.c

+0 −22
Original line number Diff line number Diff line
@@ -68,25 +68,3 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len) 
}

EXPORT_SYMBOL(csum_partial_copy_nocheck);

__sum16 csum_ipv6_magic(const struct in6_addr *saddr,

			const struct in6_addr *daddr,

			__u32 len, __u8 proto, __wsum sum)

{

	__u64 rest, sum64;



	rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) +

		(__force __u64)sum;



	asm("	addq (%[saddr]),%[sum]\n"

	    "	adcq 8(%[saddr]),%[sum]\n"

	    "	adcq (%[daddr]),%[sum]\n"

	    "	adcq 8(%[daddr]),%[sum]\n"

	    "	adcq $0,%[sum]\n"



	    : [sum] "=r" (sum64)

	    : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr));



	return csum_fold(

	       (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));

}

EXPORT_SYMBOL(csum_ipv6_magic);