a25b931684
The KVM code has some repeated bugs in it around use of __pa() on per-cpu data. Those data are not in an area on which using __pa() is valid. However, they are also called early enough in boot that __vmalloc_start_set is not set, and thus the CONFIG_DEBUG_VIRTUAL debugging does not catch them. This adds a check to also verify __pa() calls against max_low_pfn, which we can use earler in boot than is_vmalloc_addr(). However, if we are super-early in boot, max_low_pfn=0 and this will trip on every call, so also make sure that max_low_pfn is set before we try to use it. With this patch applied, CONFIG_DEBUG_VIRTUAL will actually catch the bug I was chasing (and fix later in this series). I'd love to find a generic way so that any __pa() call on percpu areas could do a BUG_ON(), but there don't appear to be any nice and easy ways to check if an address is a percpu one. Anybody have ideas on a way to do this? Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20130122212430.F46F8159@kernel.stglabs.ibm.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
98 lines
2.2 KiB
C
98 lines
2.2 KiB
C
#include <linux/bootmem.h>
|
|
#include <linux/mmdebug.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mm.h>
|
|
|
|
#include <asm/page.h>
|
|
|
|
#include "physaddr.h"
|
|
|
|
#ifdef CONFIG_X86_64
|
|
|
|
#ifdef CONFIG_DEBUG_VIRTUAL
|
|
unsigned long __phys_addr(unsigned long x)
|
|
{
|
|
unsigned long y = x - __START_KERNEL_map;
|
|
|
|
/* use the carry flag to determine if x was < __START_KERNEL_map */
|
|
if (unlikely(x > y)) {
|
|
x = y + phys_base;
|
|
|
|
VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
|
|
} else {
|
|
x = y + (__START_KERNEL_map - PAGE_OFFSET);
|
|
|
|
/* carry flag will be set if starting x was >= PAGE_OFFSET */
|
|
VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x));
|
|
}
|
|
|
|
return x;
|
|
}
|
|
EXPORT_SYMBOL(__phys_addr);
|
|
|
|
unsigned long __phys_addr_symbol(unsigned long x)
|
|
{
|
|
unsigned long y = x - __START_KERNEL_map;
|
|
|
|
/* only check upper bounds since lower bounds will trigger carry */
|
|
VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
|
|
|
|
return y + phys_base;
|
|
}
|
|
EXPORT_SYMBOL(__phys_addr_symbol);
|
|
#endif
|
|
|
|
bool __virt_addr_valid(unsigned long x)
|
|
{
|
|
unsigned long y = x - __START_KERNEL_map;
|
|
|
|
/* use the carry flag to determine if x was < __START_KERNEL_map */
|
|
if (unlikely(x > y)) {
|
|
x = y + phys_base;
|
|
|
|
if (y >= KERNEL_IMAGE_SIZE)
|
|
return false;
|
|
} else {
|
|
x = y + (__START_KERNEL_map - PAGE_OFFSET);
|
|
|
|
/* carry flag will be set if starting x was >= PAGE_OFFSET */
|
|
if ((x > y) || !phys_addr_valid(x))
|
|
return false;
|
|
}
|
|
|
|
return pfn_valid(x >> PAGE_SHIFT);
|
|
}
|
|
EXPORT_SYMBOL(__virt_addr_valid);
|
|
|
|
#else
|
|
|
|
#ifdef CONFIG_DEBUG_VIRTUAL
|
|
unsigned long __phys_addr(unsigned long x)
|
|
{
|
|
unsigned long phys_addr = x - PAGE_OFFSET;
|
|
/* VMALLOC_* aren't constants */
|
|
VIRTUAL_BUG_ON(x < PAGE_OFFSET);
|
|
VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
|
|
/* max_low_pfn is set early, but not _that_ early */
|
|
if (max_low_pfn) {
|
|
VIRTUAL_BUG_ON((phys_addr >> PAGE_SHIFT) > max_low_pfn);
|
|
BUG_ON(slow_virt_to_phys((void *)x) != phys_addr);
|
|
}
|
|
return phys_addr;
|
|
}
|
|
EXPORT_SYMBOL(__phys_addr);
|
|
#endif
|
|
|
|
bool __virt_addr_valid(unsigned long x)
|
|
{
|
|
if (x < PAGE_OFFSET)
|
|
return false;
|
|
if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
|
|
return false;
|
|
if (x >= FIXADDR_START)
|
|
return false;
|
|
return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
|
|
}
|
|
EXPORT_SYMBOL(__virt_addr_valid);
|
|
|
|
#endif /* CONFIG_X86_64 */
|