From 5d8de293c224896a4da99763fce4f9794308caf4 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Fri, 29 Apr 2022 14:37:59 -0700 Subject: vmcore: convert copy_oldmem_page() to take an iov_iter Patch series "Convert vmcore to use an iov_iter", v5. For some reason several people have been sending bad patches to fix compiler warnings in vmcore recently. Here's how it should be done. Compile-tested only on x86. As noted in the first patch, s390 should take this conversion a bit further, but I'm not inclined to do that work myself. This patch (of 3): Instead of passing in a 'buf' and 'userbuf' argument, pass in an iov_iter. s390 needs more work to pass the iov_iter down further, or refactor, but I'd be more comfortable if someone who can test on s390 did that work. It's more convenient to convert the whole of read_from_oldmem() to take an iov_iter at the same time, so rename it to read_from_oldmem_iter() and add a temporary read_from_oldmem() wrapper that creates an iov_iter. Link: https://lkml.kernel.org/r/20220408090636.560886-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20220408090636.560886-2-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reviewed-by: Christoph Hellwig Cc: Heiko Carstens Signed-off-by: Andrew Morton --- arch/x86/kernel/crash_dump_32.c | 29 ++++------------------------- arch/x86/kernel/crash_dump_64.c | 41 +++++++++++------------------------------ 2 files changed, 15 insertions(+), 55 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c index 5fcac46aaf6b..5f4ae5476e19 100644 --- a/arch/x86/kernel/crash_dump_32.c +++ b/arch/x86/kernel/crash_dump_32.c @@ -10,8 +10,7 @@ #include #include #include - -#include +#include static inline bool is_crashed_pfn_valid(unsigned long pfn) { @@ -29,21 +28,8 @@ static inline bool is_crashed_pfn_valid(unsigned long pfn) #endif } -/** - * copy_oldmem_page - copy one page from "oldmem" - * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) - * @csize: number of bytes to copy - * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). - * - * Copy a page from "oldmem". For this page, there might be no pte mapped - * in the current kernel. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize, + unsigned long offset) { void *vaddr; @@ -54,14 +40,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, return -EFAULT; vaddr = kmap_local_pfn(pfn); - - if (!userbuf) { - memcpy(buf, vaddr + offset, csize); - } else { - if (copy_to_user(buf, vaddr + offset, csize)) - csize = -EFAULT; - } - + csize = copy_to_iter(vaddr + offset, csize, iter); kunmap_local(vaddr); return csize; diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c index 97529552dd24..94fe4aff9694 100644 --- a/arch/x86/kernel/crash_dump_64.c +++ b/arch/x86/kernel/crash_dump_64.c @@ -8,12 +8,12 @@ #include #include -#include +#include #include #include -static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf, +static ssize_t __copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset, bool encrypted) { void *vaddr; @@ -29,46 +29,27 @@ static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, if (!vaddr) return -ENOMEM; - if (userbuf) { - if (copy_to_user((void __user *)buf, vaddr + offset, csize)) { - iounmap((void __iomem *)vaddr); - return -EFAULT; - } - } else - memcpy(buf, vaddr + offset, csize); + csize = copy_to_iter(vaddr + offset, csize, iter); iounmap((void __iomem *)vaddr); return csize; } -/** - * copy_oldmem_page - copy one page of memory - * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) - * @csize: number of bytes to copy - * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). - * - * Copy a page from the old kernel's memory. For this page, there is no pte - * mapped in the current kernel. We stitch up a pte, similar to kmap_atomic. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize, + unsigned long offset) { - return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, false); + return __copy_oldmem_page(iter, pfn, csize, offset, false); } -/** +/* * copy_oldmem_page_encrypted - same as copy_oldmem_page() above but ioremap the * memory with the encryption mask set to accommodate kdump on SME-enabled * machines. */ -ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset) { - return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true); + return __copy_oldmem_page(iter, pfn, csize, offset, true); } ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos) -- cgit v1.2.3 From e0690479917cbce740eef51fa3de92c69647a5ad Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Fri, 29 Apr 2022 14:37:59 -0700 Subject: vmcore: convert read_from_oldmem() to take an iov_iter Remove the read_from_oldmem() wrapper introduced earlier and convert all the remaining callers to pass an iov_iter. Link: https://lkml.kernel.org/r/20220408090636.560886-4-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reviewed-by: Christoph Hellwig Cc: Tiezhu Yang Cc: Amit Daniel Kachhap Cc: Al Viro Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- arch/x86/kernel/crash_dump_64.c | 7 ++++++- fs/proc/vmcore.c | 40 +++++++++++++++------------------------- include/linux/crash_dump.h | 10 ++++------ 3 files changed, 25 insertions(+), 32 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c index 94fe4aff9694..e75bc2f217ff 100644 --- a/arch/x86/kernel/crash_dump_64.c +++ b/arch/x86/kernel/crash_dump_64.c @@ -54,6 +54,11 @@ ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn, ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos) { - return read_from_oldmem(buf, count, ppos, 0, + struct kvec kvec = { .iov_base = buf, .iov_len = count }; + struct iov_iter iter; + + iov_iter_kvec(&iter, READ, &kvec, 1, count); + + return read_from_oldmem(&iter, count, ppos, cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)); } diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 4a721865b5cd..4eaeb645e759 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -129,7 +129,7 @@ static int open_vmcore(struct inode *inode, struct file *file) } /* Reads a page from the oldmem device from given offset. */ -static ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count, +ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, u64 *ppos, bool encrypted) { unsigned long pfn, offset; @@ -178,27 +178,6 @@ static ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count, return read; } -ssize_t read_from_oldmem(char *buf, size_t count, - u64 *ppos, int userbuf, - bool encrypted) -{ - struct iov_iter iter; - struct iovec iov; - struct kvec kvec; - - if (userbuf) { - iov.iov_base = (__force void __user *)buf; - iov.iov_len = count; - iov_iter_init(&iter, READ, &iov, 1, count); - } else { - kvec.iov_base = buf; - kvec.iov_len = count; - iov_iter_kvec(&iter, READ, &kvec, 1, count); - } - - return read_from_oldmem_iter(&iter, count, ppos, encrypted); -} - /* * Architectures may override this function to allocate ELF header in 2nd kernel */ @@ -218,7 +197,12 @@ void __weak elfcorehdr_free(unsigned long long addr) */ ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos) { - return read_from_oldmem(buf, count, ppos, 0, false); + struct kvec kvec = { .iov_base = buf, .iov_len = count }; + struct iov_iter iter; + + iov_iter_kvec(&iter, READ, &kvec, 1, count); + + return read_from_oldmem(&iter, count, ppos, false); } /* @@ -226,7 +210,13 @@ ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos) */ ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos) { - return read_from_oldmem(buf, count, ppos, 0, cc_platform_has(CC_ATTR_MEM_ENCRYPT)); + struct kvec kvec = { .iov_base = buf, .iov_len = count }; + struct iov_iter iter; + + iov_iter_kvec(&iter, READ, &kvec, 1, count); + + return read_from_oldmem(&iter, count, ppos, + cc_platform_has(CC_ATTR_MEM_ENCRYPT)); } /* @@ -402,7 +392,7 @@ static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos) m->offset + m->size - *fpos, iov_iter_count(iter)); start = m->paddr + *fpos - m->offset; - tmp = read_from_oldmem_iter(iter, tsz, &start, + tmp = read_from_oldmem(iter, tsz, &start, cc_platform_has(CC_ATTR_MEM_ENCRYPT)); if (tmp < 0) return tmp; diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h index a1cf7d5c03c7..0f3a656293b0 100644 --- a/include/linux/crash_dump.h +++ b/include/linux/crash_dump.h @@ -134,13 +134,11 @@ static inline int vmcore_add_device_dump(struct vmcoredd_data *data) #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ #ifdef CONFIG_PROC_VMCORE -ssize_t read_from_oldmem(char *buf, size_t count, - u64 *ppos, int userbuf, - bool encrypted); +ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, + u64 *ppos, bool encrypted); #else -static inline ssize_t read_from_oldmem(char *buf, size_t count, - u64 *ppos, int userbuf, - bool encrypted) +static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, + u64 *ppos, bool encrypted) { return -EOPNOTSUPP; } -- cgit v1.2.3 From 6308499b5e99c0c903fde2c605e41d9a86c4be6c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 29 Apr 2022 14:37:59 -0700 Subject: net: unexport csum_and_copy_{from,to}_user csum_and_copy_from_user and csum_and_copy_to_user are exported by a few architectures, but not actually used in modular code. Drop the exports. Link: https://lkml.kernel.org/r/20220421070440.1282704-1-hch@lst.de Signed-off-by: Christoph Hellwig Acked-by: Jakub Kicinski Acked-by: Geert Uytterhoeven Acked-by: Arnd Bergmann Acked-by: Michael Ellerman (powerpc) Cc: David Miller Signed-off-by: Andrew Morton --- arch/alpha/lib/csum_partial_copy.c | 1 - arch/m68k/lib/checksum.c | 2 -- arch/powerpc/lib/checksum_wrappers.c | 2 -- arch/x86/lib/csum-wrappers_64.c | 2 -- 4 files changed, 7 deletions(-) (limited to 'arch/x86') diff --git a/arch/alpha/lib/csum_partial_copy.c b/arch/alpha/lib/csum_partial_copy.c index 1931a04af85a..4d180d96f09e 100644 --- a/arch/alpha/lib/csum_partial_copy.c +++ b/arch/alpha/lib/csum_partial_copy.c @@ -353,7 +353,6 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len) return 0; return __csum_and_copy(src, dst, len); } -EXPORT_SYMBOL(csum_and_copy_from_user); __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len) diff --git a/arch/m68k/lib/checksum.c b/arch/m68k/lib/checksum.c index 7e6afeae6217..5acb821849d3 100644 --- a/arch/m68k/lib/checksum.c +++ b/arch/m68k/lib/checksum.c @@ -265,8 +265,6 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len) return sum; } -EXPORT_SYMBOL(csum_and_copy_from_user); - /* * copy from kernel space while checksumming, otherwise like csum_partial diff --git a/arch/powerpc/lib/checksum_wrappers.c b/arch/powerpc/lib/checksum_wrappers.c index f3999cbb2fcc..1a14c8780278 100644 --- a/arch/powerpc/lib/checksum_wrappers.c +++ b/arch/powerpc/lib/checksum_wrappers.c @@ -24,7 +24,6 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst, user_read_access_end(); return csum; } -EXPORT_SYMBOL(csum_and_copy_from_user); __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len) { @@ -38,4 +37,3 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len) user_write_access_end(); return csum; } -EXPORT_SYMBOL(csum_and_copy_to_user); diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c index 189344924a2b..145f9a0bde29 100644 --- a/arch/x86/lib/csum-wrappers_64.c +++ b/arch/x86/lib/csum-wrappers_64.c @@ -32,7 +32,6 @@ csum_and_copy_from_user(const void __user *src, void *dst, int len) user_access_end(); return sum; } -EXPORT_SYMBOL(csum_and_copy_from_user); /** * csum_and_copy_to_user - Copy and checksum to user space. @@ -57,7 +56,6 @@ csum_and_copy_to_user(const void *src, void __user *dst, int len) user_access_end(); return sum; } -EXPORT_SYMBOL(csum_and_copy_to_user); /** * csum_partial_copy_nocheck - Copy and checksum. -- cgit v1.2.3