aboutsummaryrefslogtreecommitdiff
path: root/arch/x86
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/Kconfig.debug11
-rw-r--r--arch/x86/mm/init_32.c19
-rw-r--r--arch/x86/mm/init_64.c20
-rw-r--r--arch/x86/mm/ioremap.c29
-rw-r--r--arch/x86/mm/pat.c175
5 files changed, 240 insertions, 14 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 610aaecc19f..239fd9fba0a 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -5,6 +5,17 @@ config TRACE_IRQFLAGS_SUPPORT
source "lib/Kconfig.debug"
+config NONPROMISC_DEVMEM
+ bool "Disable promiscuous /dev/mem"
+ help
+ The /dev/mem file by default only allows userspace access to PCI
+ space and the BIOS code and data regions. This is sufficient for
+ dosemu and X and all common users of /dev/mem. With this config
+ option, you allow userspace access to all of memory, including
+ kernel and userspace memory. Accidental access to this is
+ obviously disasterous, but specific access can be used by people
+ debugging the kernel.
+
config EARLY_PRINTK
bool "Early printk" if EMBEDDED
default y
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 08aa1878fad..baf7c4f643c 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -227,6 +227,25 @@ static inline int page_kills_ppro(unsigned long pagenr)
return 0;
}
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number.
+ *
+ *
+ * On x86, access has to be given to the first megabyte of ram because that area
+ * contains bios code and data regions used by X and dosemu and similar apps.
+ * Access has to be given to non-kernel-ram areas as well, these contain the PCI
+ * mmio resources as well as potential bios/acpi data regions.
+ */
+int devmem_is_allowed(unsigned long pagenr)
+{
+ if (pagenr <= 256)
+ return 1;
+ if (!page_is_ram(pagenr))
+ return 1;
+ return 0;
+}
+
#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index b798e7b92b1..0cca6266303 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -663,6 +663,26 @@ EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
#endif /* CONFIG_MEMORY_HOTPLUG */
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number.
+ *
+ *
+ * On x86, access has to be given to the first megabyte of ram because that area
+ * contains bios code and data regions used by X and dosemu and similar apps.
+ * Access has to be given to non-kernel-ram areas as well, these contain the PCI
+ * mmio resources as well as potential bios/acpi data regions.
+ */
+int devmem_is_allowed(unsigned long pagenr)
+{
+ if (pagenr <= 256)
+ return 1;
+ if (!page_is_ram(pagenr))
+ return 1;
+ return 0;
+}
+
+
static struct kcore_list kcore_mem, kcore_vmalloc, kcore_kernel,
kcore_modules, kcore_vsyscall;
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 36a3f7ded62..d176b23110c 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -336,6 +336,35 @@ void iounmap(volatile void __iomem *addr)
}
EXPORT_SYMBOL(iounmap);
+/*
+ * Convert a physical pointer to a virtual kernel pointer for /dev/mem
+ * access
+ */
+void *xlate_dev_mem_ptr(unsigned long phys)
+{
+ void *addr;
+ unsigned long start = phys & PAGE_MASK;
+
+ /* If page is RAM, we can use __va. Otherwise ioremap and unmap. */
+ if (page_is_ram(start >> PAGE_SHIFT))
+ return __va(phys);
+
+ addr = (void *)ioremap(start, PAGE_SIZE);
+ if (addr)
+ addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK));
+
+ return addr;
+}
+
+void unxlate_dev_mem_ptr(unsigned long phys, void *addr)
+{
+ if (page_is_ram(phys >> PAGE_SHIFT))
+ return;
+
+ iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
+ return;
+}
+
#ifdef CONFIG_X86_32
int __initdata early_ioremap_debug;
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 72c0f609740..ef8b64b89c7 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -11,6 +11,7 @@
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/fs.h>
+#include <linux/bootmem.h>
#include <asm/msr.h>
#include <asm/tlbflush.h>
@@ -21,6 +22,7 @@
#include <asm/cacheflush.h>
#include <asm/fcntl.h>
#include <asm/mtrr.h>
+#include <asm/io.h>
int pat_wc_enabled = 1;
@@ -190,6 +192,21 @@ static int pat_x_mtrr_type(u64 start, u64 end, unsigned long prot,
return 0;
}
+/*
+ * req_type typically has one of the:
+ * - _PAGE_CACHE_WB
+ * - _PAGE_CACHE_WC
+ * - _PAGE_CACHE_UC_MINUS
+ * - _PAGE_CACHE_UC
+ *
+ * req_type will have a special case value '-1', when requester want to inherit
+ * the memory type from mtrr (if WB), existing PAT, defaulting to UC_MINUS.
+ *
+ * If ret_type is NULL, function will return an error if it cannot reserve the
+ * region with req_type. If ret_type is non-null, function will return
+ * available type in ret_type in case of no error. In case of any error
+ * it will return a negative return value.
+ */
int reserve_memtype(u64 start, u64 end, unsigned long req_type,
unsigned long *ret_type)
{
@@ -200,9 +217,14 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
/* Only track when pat_wc_enabled */
if (!pat_wc_enabled) {
- if (ret_type)
- *ret_type = req_type;
-
+ /* This is identical to page table setting without PAT */
+ if (ret_type) {
+ if (req_type == -1) {
+ *ret_type = _PAGE_CACHE_WB;
+ } else {
+ *ret_type = req_type;
+ }
+ }
return 0;
}
@@ -214,8 +236,29 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
return 0;
}
- req_type &= _PAGE_CACHE_MASK;
- err = pat_x_mtrr_type(start, end, req_type, &actual_type);
+ if (req_type == -1) {
+ /*
+ * Special case where caller wants to inherit from mtrr or
+ * existing pat mapping, defaulting to UC_MINUS in case of
+ * no match.
+ */
+ u8 mtrr_type = mtrr_type_lookup(start, end);
+ if (mtrr_type == 0xFE) { /* MTRR match error */
+ err = -1;
+ }
+
+ if (mtrr_type == MTRR_TYPE_WRBACK) {
+ req_type = _PAGE_CACHE_WB;
+ actual_type = _PAGE_CACHE_WB;
+ } else {
+ req_type = _PAGE_CACHE_UC_MINUS;
+ actual_type = _PAGE_CACHE_UC_MINUS;
+ }
+ } else {
+ req_type &= _PAGE_CACHE_MASK;
+ err = pat_x_mtrr_type(start, end, req_type, &actual_type);
+ }
+
if (err) {
if (ret_type)
*ret_type = actual_type;
@@ -241,7 +284,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
struct memtype *saved_ptr;
if (parse->start >= end) {
- printk("New Entry\n");
+ pr_debug("New Entry\n");
list_add(&new_entry->nd, parse->nd.prev);
new_entry = NULL;
break;
@@ -343,7 +386,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
break;
}
- printk("Overlap at 0x%Lx-0x%Lx\n",
+ printk(KERN_INFO "Overlap at 0x%Lx-0x%Lx\n",
saved_ptr->start, saved_ptr->end);
/* No conflict. Go ahead and add this new entry */
list_add(&new_entry->nd, &saved_ptr->nd);
@@ -353,7 +396,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
}
if (err) {
- printk(
+ printk(KERN_INFO
"reserve_memtype failed 0x%Lx-0x%Lx, track %s, req %s\n",
start, end, cattr_name(new_entry->type),
cattr_name(req_type));
@@ -365,16 +408,16 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
if (new_entry) {
/* No conflict. Not yet added to the list. Add to the tail */
list_add_tail(&new_entry->nd, &memtype_list);
- printk("New Entry\n");
- }
+ pr_debug("New Entry\n");
+ }
if (ret_type) {
- printk(
+ pr_debug(
"reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
start, end, cattr_name(actual_type),
cattr_name(req_type), cattr_name(*ret_type));
} else {
- printk(
+ pr_debug(
"reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s\n",
start, end, cattr_name(actual_type),
cattr_name(req_type));
@@ -411,11 +454,115 @@ int free_memtype(u64 start, u64 end)
spin_unlock(&memtype_lock);
if (err) {
- printk(KERN_DEBUG "%s:%d freeing invalid memtype %Lx-%Lx\n",
+ printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
current->comm, current->pid, start, end);
}
- printk( "free_memtype request 0x%Lx-0x%Lx\n", start, end);
+ pr_debug("free_memtype request 0x%Lx-0x%Lx\n", start, end);
return err;
}
+
+/*
+ * /dev/mem mmap interface. The memtype used for mapping varies:
+ * - Use UC for mappings with O_SYNC flag
+ * - Without O_SYNC flag, if there is any conflict in reserve_memtype,
+ * inherit the memtype from existing mapping.
+ * - Else use UC_MINUS memtype (for backward compatibility with existing
+ * X drivers.
+ */
+pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
+ unsigned long size, pgprot_t vma_prot)
+{
+ return vma_prot;
+}
+
+int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
+ unsigned long size, pgprot_t *vma_prot)
+{
+ u64 offset = ((u64) pfn) << PAGE_SHIFT;
+ unsigned long flags = _PAGE_CACHE_UC_MINUS;
+ unsigned long ret_flags;
+ int retval;
+
+ if (file->f_flags & O_SYNC) {
+ flags = _PAGE_CACHE_UC;
+ }
+
+#ifdef CONFIG_X86_32
+ /*
+ * On the PPro and successors, the MTRRs are used to set
+ * memory types for physical addresses outside main memory,
+ * so blindly setting UC or PWT on those pages is wrong.
+ * For Pentiums and earlier, the surround logic should disable
+ * caching for the high addresses through the KEN pin, but
+ * we maintain the tradition of paranoia in this code.
+ */
+ if (!pat_wc_enabled &&
+ ! ( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
+ test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
+ test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
+ test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability)) &&
+ (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
+ flags = _PAGE_CACHE_UC;
+ }
+#endif
+
+ /*
+ * With O_SYNC, we can only take UC mapping. Fail if we cannot.
+ * Without O_SYNC, we want to get
+ * - WB for WB-able memory and no other conflicting mappings
+ * - UC_MINUS for non-WB-able memory with no other conflicting mappings
+ * - Inherit from confliting mappings otherwise
+ */
+ if (flags != _PAGE_CACHE_UC_MINUS) {
+ retval = reserve_memtype(offset, offset + size, flags, NULL);
+ } else {
+ retval = reserve_memtype(offset, offset + size, -1, &ret_flags);
+ }
+
+ if (retval < 0)
+ return 0;
+
+ flags = ret_flags;
+
+ if (pfn <= max_pfn_mapped &&
+ ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
+ free_memtype(offset, offset + size);
+ printk(KERN_INFO
+ "%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n",
+ current->comm, current->pid,
+ cattr_name(flags),
+ offset, offset + size);
+ return 0;
+ }
+
+ *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
+ flags);
+ return 1;
+}
+
+void map_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
+{
+ u64 addr = (u64)pfn << PAGE_SHIFT;
+ unsigned long flags;
+ unsigned long want_flags = (pgprot_val(vma_prot) & _PAGE_CACHE_MASK);
+
+ reserve_memtype(addr, addr + size, want_flags, &flags);
+ if (flags != want_flags) {
+ printk(KERN_INFO
+ "%s:%d /dev/mem expected mapping type %s for %Lx-%Lx, got %s\n",
+ current->comm, current->pid,
+ cattr_name(want_flags),
+ addr, addr + size,
+ cattr_name(flags));
+ }
+}
+
+void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
+{
+ u64 addr = (u64)pfn << PAGE_SHIFT;
+
+ free_memtype(addr, addr + size);
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-14 08:03:25 +0000