* [PATCH v3] RISC-V: Remove any memblock representing unusable memory area
@ 2020-10-01 19:05 Atish Patra
2020-10-02 10:12 ` Anup Patel
2020-10-04 23:22 ` Palmer Dabbelt
0 siblings, 2 replies; 3+ messages in thread
From: Atish Patra @ 2020-10-01 19:05 UTC (permalink / raw)
To: linux-kernel
Cc: Albert Ou, Anup Patel, Mike Rapoport, Atish Patra,
Palmer Dabbelt, Zong Li, Paul Walmsley, linux-riscv
RISC-V limits the physical memory size by -PAGE_OFFSET. Any memory beyond
that size from DRAM start is unusable. Just remove any memblock pointing
to those memory region without worrying about computing the maximum size.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
---
Changes from v2->v3
Updated comment as per Mike's suggestion.
---
arch/riscv/mm/init.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index ca03762a3733..564e0be677b7 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -146,8 +146,6 @@ static phys_addr_t dtb_early_pa __initdata;
void __init setup_bootmem(void)
{
struct memblock_region *reg;
- phys_addr_t mem_size = 0;
- phys_addr_t total_mem = 0;
phys_addr_t mem_start, end = 0;
phys_addr_t vmlinux_end = __pa_symbol(&_end);
phys_addr_t vmlinux_start = __pa_symbol(&_start);
@@ -155,21 +153,18 @@ void __init setup_bootmem(void)
/* Find the memory region containing the kernel */
for_each_memblock(memory, reg) {
end = reg->base + reg->size;
- if (!total_mem)
+ if (!mem_start)
mem_start = reg->base;
if (reg->base <= vmlinux_start && vmlinux_end <= end)
BUG_ON(reg->size == 0);
- total_mem = total_mem + reg->size;
}
/*
- * Remove memblock from the end of usable area to the
- * end of region
+ * The maximal physical memory size is -PAGE_OFFSET.
+ * Make sure that any memory beyond mem_start + (-PAGE_OFFSET) is removed
+ * as it is unusable by kernel.
*/
- mem_size = min(total_mem, (phys_addr_t)-PAGE_OFFSET);
- if (mem_start + mem_size < end)
- memblock_remove(mem_start + mem_size,
- end - mem_start - mem_size);
+ memblock_enforce_memory_limit(mem_start - PAGE_OFFSET);
/* Reserve from the start of the kernel to the end of the kernel */
memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
--
2.25.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v3] RISC-V: Remove any memblock representing unusable memory area
2020-10-01 19:05 [PATCH v3] RISC-V: Remove any memblock representing unusable memory area Atish Patra
@ 2020-10-02 10:12 ` Anup Patel
2020-10-04 23:22 ` Palmer Dabbelt
1 sibling, 0 replies; 3+ messages in thread
From: Anup Patel @ 2020-10-02 10:12 UTC (permalink / raw)
To: Atish Patra
Cc: Albert Ou, Anup Patel, linux-kernel@vger.kernel.org List,
Mike Rapoport, Palmer Dabbelt, Zong Li, Paul Walmsley,
linux-riscv
On Fri, Oct 2, 2020 at 12:36 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> RISC-V limits the physical memory size by -PAGE_OFFSET. Any memory beyond
> that size from DRAM start is unusable. Just remove any memblock pointing
> to those memory region without worrying about computing the maximum size.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
>
> ---
> Changes from v2->v3
> Updated comment as per Mike's suggestion.
> ---
> arch/riscv/mm/init.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index ca03762a3733..564e0be677b7 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -146,8 +146,6 @@ static phys_addr_t dtb_early_pa __initdata;
> void __init setup_bootmem(void)
> {
> struct memblock_region *reg;
> - phys_addr_t mem_size = 0;
> - phys_addr_t total_mem = 0;
> phys_addr_t mem_start, end = 0;
> phys_addr_t vmlinux_end = __pa_symbol(&_end);
> phys_addr_t vmlinux_start = __pa_symbol(&_start);
> @@ -155,21 +153,18 @@ void __init setup_bootmem(void)
> /* Find the memory region containing the kernel */
> for_each_memblock(memory, reg) {
> end = reg->base + reg->size;
> - if (!total_mem)
> + if (!mem_start)
> mem_start = reg->base;
> if (reg->base <= vmlinux_start && vmlinux_end <= end)
> BUG_ON(reg->size == 0);
> - total_mem = total_mem + reg->size;
> }
>
> /*
> - * Remove memblock from the end of usable area to the
> - * end of region
> + * The maximal physical memory size is -PAGE_OFFSET.
> + * Make sure that any memory beyond mem_start + (-PAGE_OFFSET) is removed
> + * as it is unusable by kernel.
> */
> - mem_size = min(total_mem, (phys_addr_t)-PAGE_OFFSET);
> - if (mem_start + mem_size < end)
> - memblock_remove(mem_start + mem_size,
> - end - mem_start - mem_size);
> + memblock_enforce_memory_limit(mem_start - PAGE_OFFSET);
>
> /* Reserve from the start of the kernel to the end of the kernel */
> memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
> --
> 2.25.1
>
Looks good to me.
Reviewed-by: Anup Patel <anup@brainfault.org>
Regards,
Anup
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v3] RISC-V: Remove any memblock representing unusable memory area
2020-10-01 19:05 [PATCH v3] RISC-V: Remove any memblock representing unusable memory area Atish Patra
2020-10-02 10:12 ` Anup Patel
@ 2020-10-04 23:22 ` Palmer Dabbelt
1 sibling, 0 replies; 3+ messages in thread
From: Palmer Dabbelt @ 2020-10-04 23:22 UTC (permalink / raw)
To: Atish Patra
Cc: aou, Anup Patel, linux-kernel, rppt, Atish Patra, zong.li,
Paul Walmsley, linux-riscv
On Thu, 01 Oct 2020 12:05:57 PDT (-0700), Atish Patra wrote:
> RISC-V limits the physical memory size by -PAGE_OFFSET. Any memory beyond
> that size from DRAM start is unusable. Just remove any memblock pointing
> to those memory region without worrying about computing the maximum size.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
>
> ---
> Changes from v2->v3
> Updated comment as per Mike's suggestion.
> ---
> arch/riscv/mm/init.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index ca03762a3733..564e0be677b7 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -146,8 +146,6 @@ static phys_addr_t dtb_early_pa __initdata;
> void __init setup_bootmem(void)
> {
> struct memblock_region *reg;
> - phys_addr_t mem_size = 0;
> - phys_addr_t total_mem = 0;
> phys_addr_t mem_start, end = 0;
> phys_addr_t vmlinux_end = __pa_symbol(&_end);
> phys_addr_t vmlinux_start = __pa_symbol(&_start);
> @@ -155,21 +153,18 @@ void __init setup_bootmem(void)
> /* Find the memory region containing the kernel */
> for_each_memblock(memory, reg) {
> end = reg->base + reg->size;
> - if (!total_mem)
> + if (!mem_start)
> mem_start = reg->base;
> if (reg->base <= vmlinux_start && vmlinux_end <= end)
> BUG_ON(reg->size == 0);
> - total_mem = total_mem + reg->size;
> }
>
> /*
> - * Remove memblock from the end of usable area to the
> - * end of region
> + * The maximal physical memory size is -PAGE_OFFSET.
> + * Make sure that any memory beyond mem_start + (-PAGE_OFFSET) is removed
> + * as it is unusable by kernel.
> */
> - mem_size = min(total_mem, (phys_addr_t)-PAGE_OFFSET);
> - if (mem_start + mem_size < end)
> - memblock_remove(mem_start + mem_size,
> - end - mem_start - mem_size);
> + memblock_enforce_memory_limit(mem_start - PAGE_OFFSET);
>
> /* Reserve from the start of the kernel to the end of the kernel */
> memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
Thanks, this is on for-next.
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2020-10-01 19:05 [PATCH v3] RISC-V: Remove any memblock representing unusable memory area Atish Patra
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2020-10-04 23:22 ` Palmer Dabbelt
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