From a6304272b03ece97346f16923453f7e36ec19a5a Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Thu, 14 Sep 2023 11:31:34 +0800 Subject: crash_core.c: remove unnecessary parameter of function Patch series "kdump: use generic functions to simplify crashkernel reservation in arch", v3. In the current arm64, crashkernel=,high support has been finished after several rounds of posting and careful reviewing. The code in arm64 which parses crashkernel kernel parameters firstly, then reserve memory can be a good example for other ARCH to refer to. Whereas in x86_64, the code mixing crashkernel parameter parsing and memory reserving is twisted, and looks messy. Refactoring the code to make it more readable maintainable is necessary. Here, firstly abstract the crashkernel parameter parsing code into parse_crashkernel() to make it be able to parse crashkernel=,high|low. Then abstract the crashkernel memory reserving code into a generic function reserve_crashkernel_generic(). Finally, in ARCH which crashkernel=,high support is needed, a simple arch_reserve_crashkernel() can be added to call above two functions. This can remove the duplicated implmentation code in each ARCH, like arm64, x86_64 and riscv. crashkernel=512M,high crashkernel=512M,high crashkernel=256M,low crashkernel=512M,high crashkernel=0M,low crashkernel=0M,high crashkernel=256M,low crashkernel=512M crashkernel=512M@0x4f000000 crashkernel=1G-4G:256M,4G-64G:320M,64G-:576M crashkernel=0M This patch (of 9): In all call sites of __parse_crashkernel(), the parameter 'name' is hardcoded as "crashkernel=". So remove the unnecessary parameter 'name', add local varibale 'name' inside __parse_crashkernel() instead. Link: https://lkml.kernel.org/r/20230914033142.676708-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20230914033142.676708-2-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Zhen Lei Cc: Catalin Marinas Cc: Chen Jiahao Cc: Zhen Lei Signed-off-by: Andrew Morton --- kernel/crash_core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel/crash_core.c') diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 2f675ef045d4..507113932aa9 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -248,11 +248,11 @@ static int __init __parse_crashkernel(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, unsigned long long *crash_base, - const char *name, const char *suffix) { char *first_colon, *first_space; char *ck_cmdline; + char *name = "crashkernel="; BUG_ON(!crash_size || !crash_base); *crash_size = 0; @@ -290,7 +290,7 @@ int __init parse_crashkernel(char *cmdline, unsigned long long *crash_base) { return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, - "crashkernel=", NULL); + NULL); } int __init parse_crashkernel_high(char *cmdline, @@ -299,7 +299,7 @@ int __init parse_crashkernel_high(char *cmdline, unsigned long long *crash_base) { return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, - "crashkernel=", suffix_tbl[SUFFIX_HIGH]); + suffix_tbl[SUFFIX_HIGH]); } int __init parse_crashkernel_low(char *cmdline, @@ -308,7 +308,7 @@ int __init parse_crashkernel_low(char *cmdline, unsigned long long *crash_base) { return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, - "crashkernel=", suffix_tbl[SUFFIX_LOW]); + suffix_tbl[SUFFIX_LOW]); } /* -- cgit From a9e1a3d84e4a0ea560ed4d84c28d06dbfdffed22 Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Thu, 14 Sep 2023 11:31:35 +0800 Subject: crash_core: change the prototype of function parse_crashkernel() Add two parameters 'low_size' and 'high' to function parse_crashkernel(), later crashkernel=,high|low parsing will be added. Make adjustments in all call sites of parse_crashkernel() in arch. Link: https://lkml.kernel.org/r/20230914033142.676708-3-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Zhen Lei Cc: Catalin Marinas Cc: Chen Jiahao Signed-off-by: Andrew Morton --- kernel/crash_core.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'kernel/crash_core.c') diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 507113932aa9..33ced5b5ed4e 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -287,10 +287,19 @@ static int __init __parse_crashkernel(char *cmdline, int __init parse_crashkernel(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, - unsigned long long *crash_base) + unsigned long long *crash_base, + unsigned long long *low_size, + bool *high) { - return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, - NULL); + int ret; + + /* crashkernel=X[@offset] */ + ret = __parse_crashkernel(cmdline, system_ram, crash_size, + crash_base, NULL); + if (!high) + return ret; + + return 0; } int __init parse_crashkernel_high(char *cmdline, -- cgit From 70916e9c8d9f1a286c99727072b22e395097909f Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Thu, 14 Sep 2023 11:31:36 +0800 Subject: crash_core: change parse_crashkernel() to support crashkernel=,high|low parsing Now parse_crashkernel() is a real entry point for all kinds of crahskernel parsing on any architecture. And wrap the crahskernel=,high|low handling inside CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION ifdeffery scope. Link: https://lkml.kernel.org/r/20230914033142.676708-4-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Zhen Lei Cc: Catalin Marinas Cc: Chen Jiahao Signed-off-by: Andrew Morton --- kernel/crash_core.c | 36 +++++++++++++++++++++++++++++++++--- 1 file changed, 33 insertions(+), 3 deletions(-) (limited to 'kernel/crash_core.c') diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 33ced5b5ed4e..99a243540a35 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -283,6 +283,9 @@ static int __init __parse_crashkernel(char *cmdline, /* * That function is the entry point for command line parsing and should be * called from the arch-specific code. + * + * If crashkernel=,high|low is supported on architecture, non-NULL values + * should be passed to parameters 'low_size' and 'high'. */ int __init parse_crashkernel(char *cmdline, unsigned long long system_ram, @@ -296,10 +299,37 @@ int __init parse_crashkernel(char *cmdline, /* crashkernel=X[@offset] */ ret = __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, NULL); - if (!high) - return ret; +#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION + /* + * If non-NULL 'high' passed in and no normal crashkernel + * setting detected, try parsing crashkernel=,high|low. + */ + if (high && ret == -ENOENT) { + ret = __parse_crashkernel(cmdline, 0, crash_size, + crash_base, suffix_tbl[SUFFIX_HIGH]); + if (ret || !*crash_size) + return -EINVAL; - return 0; + /* + * crashkernel=Y,low can be specified or not, but invalid value + * is not allowed. + */ + ret = __parse_crashkernel(cmdline, 0, low_size, + crash_base, suffix_tbl[SUFFIX_LOW]); + if (ret == -ENOENT) { + *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; + ret = 0; + } else if (ret) { + return ret; + } + + *high = true; + } +#endif + if (!*crash_size) + ret = -EINVAL; + + return ret; } int __init parse_crashkernel_high(char *cmdline, -- cgit From 0ab97169aa0517079b22c2e64192906caa5dc6d5 Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Thu, 14 Sep 2023 11:31:37 +0800 Subject: crash_core: add generic function to do reservation In architecture like x86_64, arm64 and riscv, they have vast virtual address space and usually have huge physical memory RAM. Their crashkernel reservation doesn't have to be limited under 4G RAM, but can be extended to the whole physical memory via crashkernel=,high support. Now add function reserve_crashkernel_generic() to reserve crashkernel memory if users specify any case of kernel pamameters, like crashkernel=xM[@offset] or crashkernel=,high|low. This is preparation to simplify code of crashkernel=,high support in architecutures. Link: https://lkml.kernel.org/r/20230914033142.676708-5-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Zhen Lei Cc: Catalin Marinas Cc: Chen Jiahao Signed-off-by: Andrew Morton --- kernel/crash_core.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 106 insertions(+), 1 deletion(-) (limited to 'kernel/crash_core.c') diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 99a243540a35..72e358197b52 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -5,7 +5,6 @@ */ #include -#include #include #include #include @@ -13,6 +12,9 @@ #include #include #include +#include +#include +#include #include #include @@ -360,6 +362,109 @@ static int __init parse_crashkernel_dummy(char *arg) } early_param("crashkernel", parse_crashkernel_dummy); +#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION +static int __init reserve_crashkernel_low(unsigned long long low_size) +{ +#ifdef CONFIG_64BIT + unsigned long long low_base; + + low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX); + if (!low_base) { + pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size); + return -ENOMEM; + } + + pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n", + low_base, low_base + low_size, low_size >> 20); + + crashk_low_res.start = low_base; + crashk_low_res.end = low_base + low_size - 1; + insert_resource(&iomem_resource, &crashk_low_res); +#endif + return 0; +} + +void __init reserve_crashkernel_generic(char *cmdline, + unsigned long long crash_size, + unsigned long long crash_base, + unsigned long long crash_low_size, + bool high) +{ + unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0; + bool fixed_base = false; + + /* User specifies base address explicitly. */ + if (crash_base) { + fixed_base = true; + search_base = crash_base; + search_end = crash_base + crash_size; + } else if (high) { + search_base = CRASH_ADDR_LOW_MAX; + search_end = CRASH_ADDR_HIGH_MAX; + } + +retry: + crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, + search_base, search_end); + if (!crash_base) { + /* + * For crashkernel=size[KMG]@offset[KMG], print out failure + * message if can't reserve the specified region. + */ + if (fixed_base) { + pr_warn("crashkernel reservation failed - memory is in use.\n"); + return; + } + + /* + * For crashkernel=size[KMG], if the first attempt was for + * low memory, fall back to high memory, the minimum required + * low memory will be reserved later. + */ + if (!high && search_end == CRASH_ADDR_LOW_MAX) { + search_end = CRASH_ADDR_HIGH_MAX; + search_base = CRASH_ADDR_LOW_MAX; + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; + goto retry; + } + + /* + * For crashkernel=size[KMG],high, if the first attempt was + * for high memory, fall back to low memory. + */ + if (high && search_end == CRASH_ADDR_HIGH_MAX) { + search_end = CRASH_ADDR_LOW_MAX; + search_base = 0; + goto retry; + } + pr_warn("cannot allocate crashkernel (size:0x%llx)\n", + crash_size); + return; + } + + if ((crash_base > CRASH_ADDR_LOW_MAX) && + crash_low_size && reserve_crashkernel_low(crash_low_size)) { + memblock_phys_free(crash_base, crash_size); + return; + } + + pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", + crash_base, crash_base + crash_size, crash_size >> 20); + + /* + * The crashkernel memory will be removed from the kernel linear + * map. Inform kmemleak so that it won't try to access it. + */ + kmemleak_ignore_phys(crash_base); + if (crashk_low_res.end) + kmemleak_ignore_phys(crashk_low_res.start); + + crashk_res.start = crash_base; + crashk_res.end = crash_base + crash_size - 1; + insert_resource(&iomem_resource, &crashk_res); +} +#endif + int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, void **addr, unsigned long *sz) { -- cgit From b631b95dded5e7f007a3a79cbaf82ef50c1e2cf7 Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Thu, 14 Sep 2023 11:31:38 +0800 Subject: crash_core: move crashk_*res definition into crash_core.c Both crashk_res and crashk_low_res are used to mark the reserved crashkernel regions in iomem_resource tree. And later the generic crashkernel resrvation will be added into crash_core.c. So move crashk_res and crashk_low_res definition into crash_core.c to avoid compiling error if CONFIG_CRASH_CORE=on while CONFIG_KEXEC_CORE is unset. Meanwhile include in if generic reservation is needed. In that case, need be added by ARCH. In asm/crash_core.h, ARCH can provide its own macro definitions to override macros in if needed. Wrap the including into CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION ifdeffery scope to avoid compiling error in other ARCH-es which don't take the generic reservation way yet. Link: https://lkml.kernel.org/r/20230914033142.676708-6-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Zhen Lei Cc: Catalin Marinas Cc: Chen Jiahao Signed-off-by: Andrew Morton --- kernel/crash_core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel/crash_core.c') diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 72e358197b52..fa8808c4f00e 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -35,6 +35,22 @@ u32 *vmcoreinfo_note; /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */ static unsigned char *vmcoreinfo_data_safecopy; +/* Location of the reserved area for the crash kernel */ +struct resource crashk_res = { + .name = "Crash kernel", + .start = 0, + .end = 0, + .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM, + .desc = IORES_DESC_CRASH_KERNEL +}; +struct resource crashk_low_res = { + .name = "Crash kernel", + .start = 0, + .end = 0, + .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM, + .desc = IORES_DESC_CRASH_KERNEL +}; + /* * parsing the "crashkernel" commandline * -- cgit From c37e56cac3d62c69f093904afbc58fc428484d14 Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Thu, 14 Sep 2023 11:31:42 +0800 Subject: crash_core.c: remove unneeded functions So far, nobody calls functions parse_crashkernel_high() and parse_crashkernel_low(), remove both of them. Link: https://lkml.kernel.org/r/20230914033142.676708-10-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Zhen Lei Cc: Catalin Marinas Cc: Chen Jiahao Signed-off-by: Andrew Morton --- kernel/crash_core.c | 18 ------------------ 1 file changed, 18 deletions(-) (limited to 'kernel/crash_core.c') diff --git a/kernel/crash_core.c b/kernel/crash_core.c index fa8808c4f00e..efe87d501c8c 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -350,24 +350,6 @@ int __init parse_crashkernel(char *cmdline, return ret; } -int __init parse_crashkernel_high(char *cmdline, - unsigned long long system_ram, - unsigned long long *crash_size, - unsigned long long *crash_base) -{ - return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, - suffix_tbl[SUFFIX_HIGH]); -} - -int __init parse_crashkernel_low(char *cmdline, - unsigned long long system_ram, - unsigned long long *crash_size, - unsigned long long *crash_base) -{ - return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, - suffix_tbl[SUFFIX_LOW]); -} - /* * Add a dummy early_param handler to mark crashkernel= as a known command line * parameter and suppress incorrect warnings in init/main.c. -- cgit