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/arm/kernel/crash_dump.c | 27 ++++---------------------- arch/arm64/kernel/crash_dump.c | 29 ++++------------------------ arch/ia64/kernel/crash_dump.c | 32 ++++--------------------------- arch/mips/kernel/crash_dump.c | 27 ++++---------------------- arch/powerpc/kernel/crash_dump.c | 35 +++++----------------------------- arch/riscv/kernel/crash_dump.c | 26 ++++--------------------- arch/s390/kernel/crash_dump.c | 13 ++++++++----- arch/sh/kernel/crash_dump.c | 29 +++++----------------------- arch/x86/kernel/crash_dump_32.c | 29 ++++------------------------ arch/x86/kernel/crash_dump_64.c | 41 +++++++++++----------------------------- 10 files changed, 53 insertions(+), 235 deletions(-) (limited to 'arch') diff --git a/arch/arm/kernel/crash_dump.c b/arch/arm/kernel/crash_dump.c index 53cb92435392..938bd932df9a 100644 --- a/arch/arm/kernel/crash_dump.c +++ b/arch/arm/kernel/crash_dump.c @@ -14,22 +14,10 @@ #include #include #include +#include -/** - * copy_oldmem_page() - copy one page from old kernel memory - * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed - * @csize: number of bytes to copy - * @offset: offset in bytes into the page - * @userbuf: if set, @buf is int he user address space - * - * This function copies one page from old kernel memory into buffer pointed by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes - * copied or negative error in case of failure. - */ -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; @@ -40,14 +28,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; - if (userbuf) { - if (copy_to_user(buf, vaddr + offset, csize)) { - iounmap(vaddr); - return -EFAULT; - } - } else { - memcpy(buf, vaddr + offset, csize); - } + csize = copy_to_iter(vaddr + offset, csize, iter); iounmap(vaddr); return csize; diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c index 58303a9ec32c..670e4ce81822 100644 --- a/arch/arm64/kernel/crash_dump.c +++ b/arch/arm64/kernel/crash_dump.c @@ -9,25 +9,11 @@ #include #include #include -#include -#include +#include #include -/** - * copy_oldmem_page() - copy one page from old kernel memory - * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed - * @csize: number of bytes to copy - * @offset: offset in bytes into the page - * @userbuf: if set, @buf is in a user address space - * - * This function copies one page from old kernel memory into buffer pointed by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes - * copied or negative error in case of failure. - */ -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; @@ -38,14 +24,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; - if (userbuf) { - if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { - memunmap(vaddr); - return -EFAULT; - } - } else { - memcpy(buf, vaddr + offset, csize); - } + csize = copy_to_iter(vaddr + offset, csize, iter); memunmap(vaddr); diff --git a/arch/ia64/kernel/crash_dump.c b/arch/ia64/kernel/crash_dump.c index 0ed3c3dee4cd..4ef68e2aa757 100644 --- a/arch/ia64/kernel/crash_dump.c +++ b/arch/ia64/kernel/crash_dump.c @@ -10,42 +10,18 @@ #include #include #include - +#include #include -#include -/** - * 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 is no pte mapped - * in the current kernel. We stitch up a pte, similar to kmap_atomic. - * - * Calling copy_to_user() in atomic context is not desirable. Hence first - * copying the data to a pre-allocated kernel page and then copying to user - * space in non-atomic context. - */ -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; if (!csize) return 0; vaddr = __va(pfn< #include +#include -/** - * 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 is 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; @@ -24,14 +12,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, return 0; 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/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c index 5693e1c67c2b..32b4a97f1b79 100644 --- a/arch/powerpc/kernel/crash_dump.c +++ b/arch/powerpc/kernel/crash_dump.c @@ -16,7 +16,7 @@ #include #include #include -#include +#include #include #include @@ -68,33 +68,8 @@ void __init setup_kdump_trampoline(void) } #endif /* CONFIG_NONSTATIC_KERNEL */ -static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize, - unsigned long offset, int userbuf) -{ - if (userbuf) { - if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) - return -EFAULT; - } else - memcpy(buf, (vaddr + offset), csize); - - return csize; -} - -/** - * 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 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) { void *vaddr; phys_addr_t paddr; @@ -107,10 +82,10 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (memblock_is_region_memory(paddr, csize)) { vaddr = __va(paddr); - csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); + csize = copy_to_iter(vaddr + offset, csize, iter); } else { vaddr = ioremap_cache(paddr, PAGE_SIZE); - csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); + csize = copy_to_iter(vaddr + offset, csize, iter); iounmap(vaddr); } diff --git a/arch/riscv/kernel/crash_dump.c b/arch/riscv/kernel/crash_dump.c index 86cc0ada5752..ea2158cee97b 100644 --- a/arch/riscv/kernel/crash_dump.c +++ b/arch/riscv/kernel/crash_dump.c @@ -7,22 +7,10 @@ #include #include +#include -/** - * copy_oldmem_page() - copy one page from old kernel memory - * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed - * @csize: number of bytes to copy - * @offset: offset in bytes into the page - * @userbuf: if set, @buf is in a user address space - * - * This function copies one page from old kernel memory into buffer pointed by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes - * copied or negative error in case of failure. - */ -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; @@ -33,13 +21,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; - if (userbuf) { - if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { - memunmap(vaddr); - return -EFAULT; - } - } else - memcpy(buf, vaddr + offset, csize); + csize = copy_to_iter(vaddr + offset, csize, iter); memunmap(vaddr); return csize; diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c index 69819b765250..a2c1c55daec0 100644 --- a/arch/s390/kernel/crash_dump.c +++ b/arch/s390/kernel/crash_dump.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -212,8 +213,8 @@ static int copy_oldmem_user(void __user *dst, unsigned long src, size_t count) /* * Copy one page from "oldmem" */ -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) { unsigned long src; int rc; @@ -221,10 +222,12 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, if (!csize) return 0; src = pfn_to_phys(pfn) + offset; - if (userbuf) - rc = copy_oldmem_user((void __force __user *) buf, src, csize); + + /* XXX: pass the iov_iter down to a common function */ + if (iter_is_iovec(iter)) + rc = copy_oldmem_user(iter->iov->iov_base, src, csize); else - rc = copy_oldmem_kernel((void *) buf, src, csize); + rc = copy_oldmem_kernel(iter->kvec->iov_base, src, csize); return rc; } diff --git a/arch/sh/kernel/crash_dump.c b/arch/sh/kernel/crash_dump.c index 5b41b59698c1..19ce6a950aac 100644 --- a/arch/sh/kernel/crash_dump.c +++ b/arch/sh/kernel/crash_dump.c @@ -8,23 +8,11 @@ #include #include #include +#include #include -/** - * 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 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) { void __iomem *vaddr; @@ -32,15 +20,8 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, return 0; vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE); - - if (userbuf) { - if (copy_to_user((void __user *)buf, (vaddr + offset), csize)) { - iounmap(vaddr); - return -EFAULT; - } - } else - memcpy(buf, (vaddr + offset), csize); - + csize = copy_to_iter(vaddr + offset, csize, iter); iounmap(vaddr); + return csize; } 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