[v3] MIPS: Add support for CONFIG_DEBUG_VIRTUAL

Commit Message

Florian Fainelli March 26, 2021, 10:14 p.m. UTC

Provide hooks to intercept bad usages of virt_to_phys() and
__pa_symbol() throughout the kernel. To make this possible, we need to
rename the current implement of virt_to_phys() into
__virt_to_phys_nodebug() and wrap it around depending on
CONFIG_DEBUG_VIRTUAL.

A similar thing is needed for __pa_symbol() which is now aliased to
__phys_addr_symbol() whose implementation is either the direct return of
RELOC_HIDE or goes through the debug version.

Signed-off-by: Florian Fainelli <[e-mail]>
---
Changes in v3:

- added missing SDPX license tag in physaddr.c

Changes in v2:
- fixed sparse warning in arch/mips/kernel/vdso.c

 arch/mips/Kconfig            |  1 +
 arch/mips/include/asm/io.h   | 14 ++++++++-
 arch/mips/include/asm/page.h |  9 +++++-
 arch/mips/kernel/vdso.c      |  2 +-
 arch/mips/mm/Makefile        |  2 ++
 arch/mips/mm/physaddr.c      | 56 ++++++++++++++++++++++++++++++++++++
 6 files changed, 81 insertions(+), 3 deletions(-)
 create mode 100644 arch/mips/mm/physaddr.c

Comments

kernel test robot March 27, 2021, 3:33 a.m. UTC | #1

Hi Florian,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.12-rc4 next-20210326]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Florian-Fainelli/MIPS-Add-support-for-CONFIG_DEBUG_VIRTUAL/20210327-061711
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 0f4498cef9f5cd18d7c6639a2a902ec1edc5be4e
config: mips-randconfig-s032-20210326 (attached as .config)
compiler: mipsel-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.3-277-gc089cd2d-dirty
        # https://github.com/0day-ci/linux/commit/ee0c68ff98559388eac4d40c8f8724e21f7ba5f6
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Florian-Fainelli/MIPS-Add-support-for-CONFIG_DEBUG_VIRTUAL/20210327-061711
        git checkout ee0c68ff98559388eac4d40c8f8724e21f7ba5f6
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=mips 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[e-mail]>


sparse warnings: (new ones prefixed by >>)
   command-line: note: in included file:
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_ACQUIRE redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_SEQ_CST redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_ACQ_REL redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_RELEASE redefined
   builtin:0:0: sparse: this was the original definition
>> arch/mips/kernel/vdso.c:161:41: sparse: sparse: cast removes address space '__iomem' of expression

vim +/__iomem +161 arch/mips/kernel/vdso.c

    88	
    89	int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
    90	{
    91		struct mips_vdso_image *image = current->thread.abi->vdso;
    92		struct mm_struct *mm = current->mm;
    93		unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn;
    94		struct vm_area_struct *vma;
    95		int ret;
    96	
    97		if (mmap_write_lock_killable(mm))
    98			return -EINTR;
    99	
   100		if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
   101			/* Map delay slot emulation page */
   102			base = mmap_region(NULL, STACK_TOP, PAGE_SIZE,
   103					VM_READ | VM_EXEC |
   104					VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
   105					0, NULL);
   106			if (IS_ERR_VALUE(base)) {
   107				ret = base;
   108				goto out;
   109			}
   110		}
   111	
   112		/*
   113		 * Determine total area size. This includes the VDSO data itself, the
   114		 * data page, and the GIC user page if present. Always create a mapping
   115		 * for the GIC user area if the GIC is present regardless of whether it
   116		 * is the current clocksource, in case it comes into use later on. We
   117		 * only map a page even though the total area is 64K, as we only need
   118		 * the counter registers at the start.
   119		 */
   120		gic_size = mips_gic_present() ? PAGE_SIZE : 0;
   121		vvar_size = gic_size + PAGE_SIZE;
   122		size = vvar_size + image->size;
   123	
   124		/*
   125		 * Find a region that's large enough for us to perform the
   126		 * colour-matching alignment below.
   127		 */
   128		if (cpu_has_dc_aliases)
   129			size += shm_align_mask + 1;
   130	
   131		base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
   132		if (IS_ERR_VALUE(base)) {
   133			ret = base;
   134			goto out;
   135		}
   136	
   137		/*
   138		 * If we suffer from dcache aliasing, ensure that the VDSO data page
   139		 * mapping is coloured the same as the kernel's mapping of that memory.
   140		 * This ensures that when the kernel updates the VDSO data userland
   141		 * will observe it without requiring cache invalidations.
   142		 */
   143		if (cpu_has_dc_aliases) {
   144			base = __ALIGN_MASK(base, shm_align_mask);
   145			base += ((unsigned long)vdso_data - gic_size) & shm_align_mask;
   146		}
   147	
   148		data_addr = base + gic_size;
   149		vdso_addr = data_addr + PAGE_SIZE;
   150	
   151		vma = _install_special_mapping(mm, base, vvar_size,
   152					       VM_READ | VM_MAYREAD,
   153					       &vdso_vvar_mapping);
   154		if (IS_ERR(vma)) {
   155			ret = PTR_ERR(vma);
   156			goto out;
   157		}
   158	
   159		/* Map GIC user page. */
   160		if (gic_size) {
 > 161			gic_pfn = virt_to_phys((void *)mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT;

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[e-mail]

Patch

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index d89efba3d8a4..0904d6351808 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -4,6 +4,7 @@  config MIPS
 	default y
 	select ARCH_32BIT_OFF_T if !64BIT
 	select ARCH_BINFMT_ELF_STATE if MIPS_FP_SUPPORT
+	select ARCH_HAS_DEBUG_VIRTUAL if !64BIT
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_PTE_SPECIAL if !(32BIT && CPU_HAS_RIXI)
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 78537aa23500..2c138450ad3b 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -100,11 +100,23 @@  static inline void set_io_port_base(unsigned long base)
  *     almost all conceivable cases a device driver should not be using
  *     this function
  */
-static inline unsigned long virt_to_phys(volatile const void *address)
+static inline unsigned long __virt_to_phys_nodebug(volatile const void *address)
 {
 	return __pa(address);
 }
 
+#ifdef CONFIG_DEBUG_VIRTUAL
+extern phys_addr_t __virt_to_phys(volatile const void *x);
+#else
+#define __virt_to_phys(x)	__virt_to_phys_nodebug(x)
+#endif
+
+#define virt_to_phys virt_to_phys
+static inline phys_addr_t virt_to_phys(const volatile void *x)
+{
+	return __virt_to_phys(x);
+}
+
 /*
  *     phys_to_virt    -       map physical address to virtual
  *     @address: address to remap
diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
index 65acab9c41f9..195ff4e9771f 100644
--- a/arch/mips/include/asm/page.h
+++ b/arch/mips/include/asm/page.h
@@ -210,9 +210,16 @@  static inline unsigned long ___pa(unsigned long x)
  * also affect MIPS so we keep this one until GCC 3.x has been retired
  * before we can apply https://patchwork.linux-mips.org/patch/1541/
  */
+#define __pa_symbol_nodebug(x)	__pa(RELOC_HIDE((unsigned long)(x), 0))
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+extern phys_addr_t __phys_addr_symbol(unsigned long x);
+#else
+#define __phys_addr_symbol(x)	__pa_symbol_nodebug(x)
+#endif
 
 #ifndef __pa_symbol
-#define __pa_symbol(x)	__pa(RELOC_HIDE((unsigned long)(x), 0))
+#define __pa_symbol(x)		__phys_addr_symbol((unsigned long)(x))
 #endif
 
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index 7d0b91ad2581..e3fd93ca480a 100644
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -158,7 +158,7 @@  int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
 	/* Map GIC user page. */
 	if (gic_size) {
-		gic_pfn = virt_to_phys(mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT;
+		gic_pfn = virt_to_phys((void *)mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT;
 
 		ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
 					 pgprot_noncached(vma->vm_page_prot));
diff --git a/arch/mips/mm/Makefile b/arch/mips/mm/Makefile
index 865926a37775..fa1f729e0700 100644
--- a/arch/mips/mm/Makefile
+++ b/arch/mips/mm/Makefile
@@ -40,3 +40,5 @@  obj-$(CONFIG_R5000_CPU_SCACHE)	+= sc-r5k.o
 obj-$(CONFIG_RM7000_CPU_SCACHE) += sc-rm7k.o
 obj-$(CONFIG_MIPS_CPU_SCACHE)	+= sc-mips.o
 obj-$(CONFIG_SCACHE_DEBUGFS)	+= sc-debugfs.o
+
+obj-$(CONFIG_DEBUG_VIRTUAL)	+= physaddr.o
diff --git a/arch/mips/mm/physaddr.c b/arch/mips/mm/physaddr.c
new file mode 100644
index 000000000000..a1ced5e44951
--- /dev/null
+++ b/arch/mips/mm/physaddr.c
@@ -0,0 +1,56 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bug.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/mmdebug.h>
+#include <linux/mm.h>
+
+#include <asm/sections.h>
+#include <asm/io.h>
+#include <asm/page.h>
+#include <asm/dma.h>
+
+static inline bool __debug_virt_addr_valid(unsigned long x)
+{
+	/* high_memory does not get immediately defined, and there
+	 * are early callers of __pa() against PAGE_OFFSET
+	 */
+	if (!high_memory && x >= PAGE_OFFSET)
+		return true;
+
+	if (high_memory && x >= PAGE_OFFSET && x < (unsigned long)high_memory)
+		return true;
+
+	/*
+	 * MAX_DMA_ADDRESS is a virtual address that may not correspond to an
+	 * actual physical address. Enough code relies on
+	 * virt_to_phys(MAX_DMA_ADDRESS) that we just need to work around it
+	 * and always return true.
+	 */
+	if (x == MAX_DMA_ADDRESS)
+		return true;
+
+	return false;
+}
+
+phys_addr_t __virt_to_phys(volatile const void *x)
+{
+	WARN(!__debug_virt_addr_valid((unsigned long)x),
+	     "virt_to_phys used for non-linear address: %pK (%pS)\n",
+	     x, x);
+
+	return __virt_to_phys_nodebug(x);
+}
+EXPORT_SYMBOL(__virt_to_phys);
+
+phys_addr_t __phys_addr_symbol(unsigned long x)
+{
+	/* This is bounds checking against the kernel image only.
+	 * __pa_symbol should only be used on kernel symbol addresses.
+	 */
+	VIRTUAL_BUG_ON(x < (unsigned long)_text ||
+		       x > (unsigned long)_end);
+
+	return __pa_symbol_nodebug(x);
+}
+EXPORT_SYMBOL(__phys_addr_symbol);