This fixes two bugs in the 2.4.17 acpitable.c. Marcello and Linus please
apply:
1) It didn't map in the entire table before doing a checksum on it, just the
header. With only one page mapped in, only the luck of BIOS table placement
avoided a MMU fault before the fault handlers were installed.
2) The authors didn't realize that fixmap pages count down from the fixed
base, so they ran off the end of virtual memory for any table over 2 pages
long.
Tested on a variety of different types of Netfinity servers, from one CPU to
eight, including a forthcoming one that has unusually large SSRT tables (the
one that found the bug).
--- 2.4.17/arch/i386/kernel/acpitable.c.df Sun Nov 11 22:15:06 2001
+++ 2.4.17/arch/i386/kernel/acpitable.c Fri Jan 11 19:36:06 2002
@@ -172,40 +172,41 @@
/*
- * Temporarily use the virtual area starting from FIX_IO_APIC_BASE_0,
+ * Temporarily use the virtual area starting from FIX_IO_APIC_BASE_END,
* to map the target physical address. The problem is that set_fixmap()
* provides a single page, and it is possible that the page is not
* sufficient.
* By using this area, we can map up to MAX_IO_APICS pages temporarily,
* i.e. until the next __va_range() call.
+ *
+ * Important Safety Note: The fixed I/O APIC page numbers are *subtracted*
+ * from the fixed base. That's why we start at FIX_IO_APIC_BASE_END and
+ * count idx down while incrementing the phys address.
*/
-static __inline__ char *
+static __init char *
__va_range(unsigned long phys, unsigned long size)
{
- unsigned long base, offset, mapped_size, mapped_phys = phys;
- int idx = FIX_IO_APIC_BASE_0;
+ unsigned long base, offset, mapped_size;
+ int idx;
offset = phys & (PAGE_SIZE - 1);
mapped_size = PAGE_SIZE - offset;
- set_fixmap(idx, mapped_phys);
- base = fix_to_virt(FIX_IO_APIC_BASE_0);
+ set_fixmap(FIX_IO_APIC_BASE_END, phys);
+ base = fix_to_virt(FIX_IO_APIC_BASE_END);
+ dprintk("__va_range(0x%lx, 0x%lx): idx=%d mapped at %lx\n", phys, size,
+ FIX_IO_APIC_BASE_END, base);
/*
* Most cases can be covered by the below.
*/
- if (mapped_size >= size)
- return ((unsigned char *) base + offset);
-
- dprintk("__va_range: mapping more than a single page, size = 0x%lx\n",
- size);
-
- do {
- if (idx++ == FIX_IO_APIC_BASE_END)
+ idx = FIX_IO_APIC_BASE_END;
+ while (mapped_size < size) {
+ if (--idx < FIX_IO_APIC_BASE_0)
return 0; /* cannot handle this */
- mapped_phys = mapped_phys + PAGE_SIZE;
- set_fixmap(idx, mapped_phys);
- mapped_size = mapped_size + PAGE_SIZE;
- } while (mapped_size < size);
+ phys += PAGE_SIZE;
+ set_fixmap(idx, phys);
+ mapped_size += PAGE_SIZE;
+ }
return ((unsigned char *) base + offset);
}
@@ -267,11 +268,14 @@
}
for (i = 0; i < tables; i++) {
-
+ /* Map in header, then map in full table length. */
header = (acpi_table_header *)
__va_range(saved_rsdt.entry[i],
sizeof(acpi_table_header));
-
+ if (!header)
+ break;
+ header = (acpi_table_header *)
+ __va_range(saved_rsdt.entry[i], header->length);
if (!header)
break;
--
James Cleverdon, IBM xSeries Platform (NUMA), Beaverton
[email protected] | [email protected]
On Wed, 16 Jan 2002 18:34:20 -0800, James Cleverdon wrote:
>This fixes two bugs in the 2.4.17 acpitable.c. Marcello and Linus please
>apply:
>...
>2) The authors didn't realize that fixmap pages count down from the fixed
>base, so they ran off the end of virtual memory for any table over 2 pages
>long.
[patch with FIX_IO_APIC_BASE (ab)use deleted]
This could probably be done more cleanly using my boot-time-ioremap
patch. I've posted it previously as part of a larger patch set (subject
"[PATCH] DMI/APIC updates"), but Linus didn't take it: it extends the
fixmap mechanism with a number of temporary boot-time maps and then
implements early boot-time versions of ioremap and iounmap using them.
It's pretty well tested by now. I'm including the 2.5.2 version
below for Linus' benefit; the 2.4.18-pre4 version can be fetched from
http://www.csd.uu.se/~mikpe/linux/kernel-patches/2.4/
Linus: If you have a suggestion for a better approach I'm all ears.
If not, consider this a request for including this patch in 2.5.3.
/Mikael
diff -ruN linux-2.5.2/arch/i386/mm/init.c linux-2.5.2.boot-time-ioremap/arch/i386/mm/init.c
--- linux-2.5.2/arch/i386/mm/init.c Tue Dec 18 00:40:11 2001
+++ linux-2.5.2.boot-time-ioremap/arch/i386/mm/init.c Thu Jan 17 09:29:54 2002
@@ -128,7 +128,6 @@
static inline void set_pte_phys (unsigned long vaddr,
unsigned long phys, pgprot_t flags)
{
- pgprot_t prot;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
@@ -144,10 +143,8 @@
return;
}
pte = pte_offset(pmd, vaddr);
- if (pte_val(*pte))
- pte_ERROR(*pte);
- pgprot_val(prot) = pgprot_val(PAGE_KERNEL) | pgprot_val(flags);
- set_pte(pte, mk_pte_phys(phys, prot));
+ /* <phys,flags> stored as-is, to permit clearing entries */
+ set_pte(pte, mk_pte_phys(phys, flags));
/*
* It's enough to flush this one mapping.
diff -ruN linux-2.5.2/arch/i386/mm/ioremap.c linux-2.5.2.boot-time-ioremap/arch/i386/mm/ioremap.c
--- linux-2.5.2/arch/i386/mm/ioremap.c Tue Mar 20 17:13:33 2001
+++ linux-2.5.2.boot-time-ioremap/arch/i386/mm/ioremap.c Thu Jan 17 09:29:58 2002
@@ -161,3 +161,68 @@
if (addr > high_memory)
return vfree((void *) (PAGE_MASK & (unsigned long) addr));
}
+
+void __init *bt_ioremap(unsigned long phys_addr, unsigned long size)
+{
+ unsigned long offset, last_addr;
+ unsigned int nrpages;
+ enum fixed_addresses idx;
+
+ /* Don't allow wraparound or zero size */
+ last_addr = phys_addr + size - 1;
+ if (!size || last_addr < phys_addr)
+ return NULL;
+
+ /*
+ * Don't remap the low PCI/ISA area, it's always mapped..
+ */
+ if (phys_addr >= 0xA0000 && last_addr < 0x100000)
+ return phys_to_virt(phys_addr);
+
+ /*
+ * Mappings have to be page-aligned
+ */
+ offset = phys_addr & ~PAGE_MASK;
+ phys_addr &= PAGE_MASK;
+ size = PAGE_ALIGN(last_addr) - phys_addr;
+
+ /*
+ * Mappings have to fit in the FIX_BTMAP area.
+ */
+ nrpages = size >> PAGE_SHIFT;
+ if (nrpages > NR_FIX_BTMAPS)
+ return NULL;
+
+ /*
+ * Ok, go for it..
+ */
+ idx = FIX_BTMAP_BEGIN;
+ while (nrpages > 0) {
+ set_fixmap(idx, phys_addr);
+ phys_addr += PAGE_SIZE;
+ --idx;
+ --nrpages;
+ }
+ return (void*) (offset + fix_to_virt(FIX_BTMAP_BEGIN));
+}
+
+void __init bt_iounmap(void *addr, unsigned long size)
+{
+ unsigned long virt_addr;
+ unsigned long offset;
+ unsigned int nrpages;
+ enum fixed_addresses idx;
+
+ virt_addr = (unsigned long)addr;
+ if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN))
+ return;
+ offset = virt_addr & ~PAGE_MASK;
+ nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
+
+ idx = FIX_BTMAP_BEGIN;
+ while (nrpages > 0) {
+ __set_fixmap(idx, 0, __pgprot(0));
+ --idx;
+ --nrpages;
+ }
+}
diff -ruN linux-2.5.2/include/asm-i386/fixmap.h linux-2.5.2.boot-time-ioremap/include/asm-i386/fixmap.h
--- linux-2.5.2/include/asm-i386/fixmap.h Thu Nov 22 20:46:19 2001
+++ linux-2.5.2.boot-time-ioremap/include/asm-i386/fixmap.h Thu Jan 17 09:29:54 2002
@@ -65,6 +65,11 @@
FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
#endif
+ __end_of_permanent_fixed_addresses,
+ /* temporary boot-time mappings, used before ioremap() is functional */
+#define NR_FIX_BTMAPS 16
+ FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
+ FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
__end_of_fixed_addresses
};
@@ -86,8 +91,8 @@
* at the top of mem..
*/
#define FIXADDR_TOP (0xffffe000UL)
-#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
-#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
+#define __FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
diff -ruN linux-2.5.2/include/asm-i386/io.h linux-2.5.2.boot-time-ioremap/include/asm-i386/io.h
--- linux-2.5.2/include/asm-i386/io.h Tue Dec 18 00:40:12 2001
+++ linux-2.5.2.boot-time-ioremap/include/asm-i386/io.h Thu Jan 17 09:29:58 2002
@@ -95,6 +95,14 @@
extern void iounmap(void *addr);
/*
+ * bt_ioremap() and bt_iounmap() are for temporary early boot-time
+ * mappings, before the real ioremap() is functional.
+ * A boot-time mapping is currently limited to at most 16 pages.
+ */
+extern void *bt_ioremap(unsigned long offset, unsigned long size);
+extern void bt_iounmap(void *addr, unsigned long size);
+
+/*
* IO bus memory addresses are also 1:1 with the physical address
*/
#define virt_to_bus virt_to_phys