Re: [PATCH v9 1/5] x86: kdump: move reserve_crashkernel_low() into crash_core.c
On 06/28/20 at 04:34pm, Chen Zhou wrote:
> In preparation for supporting reserve_crashkernel_low in arm64 as
> x86_64 does, move reserve_crashkernel_low() into kernel/crash_core.c.
>
> BTW, move x86_64 CRASH_ALIGN to 2M suggested by Dave. CONFIG_PHYSICAL_ALIGN
> can be selected from 2M to 16M, move to the same as arm64.
>
> Note, in arm64, we reserve low memory if and only if crashkernel=X,low
> is specified. Different with x86_64, don't set low memory automatically.
>
> Reported-by: kbuild test robot
> Signed-off-by: Chen Zhou
> Tested-by: John Donnelly
> Tested-by: Prabhakar Kushwaha
> ---
> arch/x86/kernel/setup.c| 66 -
> include/linux/crash_core.h | 3 ++
> include/linux/kexec.h | 2 -
> kernel/crash_core.c| 85 ++
> kernel/kexec_core.c| 17
> 5 files changed, 96 insertions(+), 77 deletions(-)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index a3767e74c758..33db99ae3035 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -401,8 +401,8 @@ static void __init
> memblock_x86_reserve_range_setup_data(void)
>
> #ifdef CONFIG_KEXEC_CORE
>
> -/* 16M alignment for crash kernel regions */
> -#define CRASH_ALIGN SZ_16M
> +/* 2M alignment for crash kernel regions */
> +#define CRASH_ALIGN SZ_2M
>
> /*
> * Keep the crash kernel below this limit.
> @@ -425,59 +425,6 @@ static void __init
> memblock_x86_reserve_range_setup_data(void)
> # define CRASH_ADDR_HIGH_MAX SZ_64T
> #endif
>
> -static int __init reserve_crashkernel_low(void)
> -{
> -#ifdef CONFIG_X86_64
> - unsigned long long base, low_base = 0, low_size = 0;
> - unsigned long total_low_mem;
> - int ret;
> -
> - total_low_mem = memblock_mem_size(1UL << (32 - PAGE_SHIFT));
> -
> - /* crashkernel=Y,low */
> - ret = parse_crashkernel_low(boot_command_line, total_low_mem,
> _size, );
> - if (ret) {
> - /*
> - * two parts from kernel/dma/swiotlb.c:
> - * -swiotlb size: user-specified with swiotlb= or default.
> - *
> - * -swiotlb overflow buffer: now hardcoded to 32k. We round it
> - * to 8M for other buffers that may need to stay low too. Also
> - * make sure we allocate enough extra low memory so that we
> - * don't run out of DMA buffers for 32-bit devices.
> - */
> - low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL
> << 20);
> - } else {
> - /* passed with crashkernel=0,low ? */
> - if (!low_size)
> - return 0;
> - }
> -
> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
> - if (!low_base) {
> - pr_err("Cannot reserve %ldMB crashkernel low memory, please try
> smaller size.\n",
> -(unsigned long)(low_size >> 20));
> - return -ENOMEM;
> - }
> -
> - ret = memblock_reserve(low_base, low_size);
> - if (ret) {
> - pr_err("%s: Error reserving crashkernel low memblock.\n",
> __func__);
> - return ret;
> - }
> -
> - pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (System
> low RAM: %ldMB)\n",
> - (unsigned long)(low_size >> 20),
> - (unsigned long)(low_base >> 20),
> - (unsigned long)(total_low_mem >> 20));
> -
> - crashk_low_res.start = low_base;
> - crashk_low_res.end = low_base + low_size - 1;
> - insert_resource(_resource, _low_res);
> -#endif
> - return 0;
> -}
> -
> static void __init reserve_crashkernel(void)
> {
> unsigned long long crash_size, crash_base, total_mem;
> @@ -541,9 +488,12 @@ static void __init reserve_crashkernel(void)
> return;
> }
>
> - if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
> - memblock_free(crash_base, crash_size);
> - return;
> + if (crash_base >= (1ULL << 32)) {
> + if (reserve_crashkernel_low()) {
> + memblock_free(crash_base, crash_size);
> + return;
> + }
> + insert_resource(_resource, _low_res);
> }
>
> pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System
> RAM: %ldMB)\n",
> diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
> index 525510a9f965..4df8c0bff03e 100644
> --- a/include/linux/crash_core.h
> +++ b/include/linux/crash_core.h
> @@ -63,6 +63,8 @@ phys_addr_t paddr_vmcoreinfo_note(void);
> extern unsigned char *vmcoreinfo_data;
> extern size_t vmcoreinfo_size;
> extern u32 *vmcoreinfo_note;
> +extern struct resource crashk_res;
> +extern struct resource crashk_low_res;
>
> Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
> void *data, size_t data_len);
> @@ -74,5 +76,6 @@
[PATCH v9 1/5] x86: kdump: move reserve_crashkernel_low() into crash_core.c
In preparation for supporting reserve_crashkernel_low in arm64 as
x86_64 does, move reserve_crashkernel_low() into kernel/crash_core.c.
BTW, move x86_64 CRASH_ALIGN to 2M suggested by Dave. CONFIG_PHYSICAL_ALIGN
can be selected from 2M to 16M, move to the same as arm64.
Note, in arm64, we reserve low memory if and only if crashkernel=X,low
is specified. Different with x86_64, don't set low memory automatically.
Reported-by: kbuild test robot
Signed-off-by: Chen Zhou
Tested-by: John Donnelly
Tested-by: Prabhakar Kushwaha
---
arch/x86/kernel/setup.c| 66 -
include/linux/crash_core.h | 3 ++
include/linux/kexec.h | 2 -
kernel/crash_core.c| 85 ++
kernel/kexec_core.c| 17
5 files changed, 96 insertions(+), 77 deletions(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index a3767e74c758..33db99ae3035 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -401,8 +401,8 @@ static void __init
memblock_x86_reserve_range_setup_data(void)
#ifdef CONFIG_KEXEC_CORE
-/* 16M alignment for crash kernel regions */
-#define CRASH_ALIGNSZ_16M
+/* 2M alignment for crash kernel regions */
+#define CRASH_ALIGNSZ_2M
/*
* Keep the crash kernel below this limit.
@@ -425,59 +425,6 @@ static void __init
memblock_x86_reserve_range_setup_data(void)
# define CRASH_ADDR_HIGH_MAX SZ_64T
#endif
-static int __init reserve_crashkernel_low(void)
-{
-#ifdef CONFIG_X86_64
- unsigned long long base, low_base = 0, low_size = 0;
- unsigned long total_low_mem;
- int ret;
-
- total_low_mem = memblock_mem_size(1UL << (32 - PAGE_SHIFT));
-
- /* crashkernel=Y,low */
- ret = parse_crashkernel_low(boot_command_line, total_low_mem,
_size, );
- if (ret) {
- /*
-* two parts from kernel/dma/swiotlb.c:
-* -swiotlb size: user-specified with swiotlb= or default.
-*
-* -swiotlb overflow buffer: now hardcoded to 32k. We round it
-* to 8M for other buffers that may need to stay low too. Also
-* make sure we allocate enough extra low memory so that we
-* don't run out of DMA buffers for 32-bit devices.
-*/
- low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL
<< 20);
- } else {
- /* passed with crashkernel=0,low ? */
- if (!low_size)
- return 0;
- }
-
- low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
- if (!low_base) {
- pr_err("Cannot reserve %ldMB crashkernel low memory, please try
smaller size.\n",
- (unsigned long)(low_size >> 20));
- return -ENOMEM;
- }
-
- ret = memblock_reserve(low_base, low_size);
- if (ret) {
- pr_err("%s: Error reserving crashkernel low memblock.\n",
__func__);
- return ret;
- }
-
- pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (System
low RAM: %ldMB)\n",
- (unsigned long)(low_size >> 20),
- (unsigned long)(low_base >> 20),
- (unsigned long)(total_low_mem >> 20));
-
- crashk_low_res.start = low_base;
- crashk_low_res.end = low_base + low_size - 1;
- insert_resource(_resource, _low_res);
-#endif
- return 0;
-}
-
static void __init reserve_crashkernel(void)
{
unsigned long long crash_size, crash_base, total_mem;
@@ -541,9 +488,12 @@ static void __init reserve_crashkernel(void)
return;
}
- if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
- memblock_free(crash_base, crash_size);
- return;
+ if (crash_base >= (1ULL << 32)) {
+ if (reserve_crashkernel_low()) {
+ memblock_free(crash_base, crash_size);
+ return;
+ }
+ insert_resource(_resource, _low_res);
}
pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System
RAM: %ldMB)\n",
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 525510a9f965..4df8c0bff03e 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -63,6 +63,8 @@ phys_addr_t paddr_vmcoreinfo_note(void);
extern unsigned char *vmcoreinfo_data;
extern size_t vmcoreinfo_size;
extern u32 *vmcoreinfo_note;
+extern struct resource crashk_res;
+extern struct resource crashk_low_res;
Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
void *data, size_t data_len);
@@ -74,5 +76,6 @@ int parse_crashkernel_high(char *cmdline, unsigned long long
system_ram,
unsigned long long *crash_size, unsigned long long *crash_base);
int parse_crashkernel_low(char
