* [PATCH v4] RISC-V: Remove any memblock representing unusable memory area
@ 2020-10-07 21:51 Atish Patra
2020-11-05 18:03 ` Palmer Dabbelt
0 siblings, 1 reply; 2+ messages in thread
From: Atish Patra @ 2020-10-07 21:51 UTC (permalink / raw)
To: linux-kernel
Cc: Atish Patra, Mike Rapoport, Albert Ou, Andrew Morton, Anup Patel,
linux-riscv, Mike Rapoport, Palmer Dabbelt, Paul Walmsley
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 v3->v4:
1. Rebased on top of for-next.
---
arch/riscv/mm/init.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 4eda1a7e8521..da43c17544c5 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -156,9 +156,8 @@ static void __init setup_initrd(void)
void __init setup_bootmem(void)
{
- phys_addr_t mem_size = 0;
- phys_addr_t total_mem = 0;
- phys_addr_t mem_start, start, end = 0;
+ phys_addr_t mem_start = 0;
+ phys_addr_t start, end = 0;
phys_addr_t vmlinux_end = __pa_symbol(&_end);
phys_addr_t vmlinux_start = __pa_symbol(&_start);
u64 i;
@@ -166,21 +165,18 @@ void __init setup_bootmem(void)
/* Find the memory region containing the kernel */
for_each_mem_range(i, &start, &end) {
phys_addr_t size = end - start;
- if (!total_mem)
+ if (!mem_start)
mem_start = start;
if (start <= vmlinux_start && vmlinux_end <= end)
BUG_ON(size == 0);
- total_mem = total_mem + 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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v4] RISC-V: Remove any memblock representing unusable memory area
2020-10-07 21:51 [PATCH v4] RISC-V: Remove any memblock representing unusable memory area Atish Patra
@ 2020-11-05 18:03 ` Palmer Dabbelt
0 siblings, 0 replies; 2+ messages in thread
From: Palmer Dabbelt @ 2020-11-05 18:03 UTC (permalink / raw)
To: Atish Patra
Cc: linux-kernel, Atish Patra, rppt, aou, akpm, Anup Patel,
linux-riscv, rppt, Paul Walmsley
On Wed, 07 Oct 2020 14:51:59 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 v3->v4:
> 1. Rebased on top of for-next.
> ---
> arch/riscv/mm/init.c | 18 +++++++-----------
> 1 file changed, 7 insertions(+), 11 deletions(-)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 4eda1a7e8521..da43c17544c5 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -156,9 +156,8 @@ static void __init setup_initrd(void)
>
> void __init setup_bootmem(void)
> {
> - phys_addr_t mem_size = 0;
> - phys_addr_t total_mem = 0;
> - phys_addr_t mem_start, start, end = 0;
> + phys_addr_t mem_start = 0;
> + phys_addr_t start, end = 0;
> phys_addr_t vmlinux_end = __pa_symbol(&_end);
> phys_addr_t vmlinux_start = __pa_symbol(&_start);
> u64 i;
> @@ -166,21 +165,18 @@ void __init setup_bootmem(void)
> /* Find the memory region containing the kernel */
> for_each_mem_range(i, &start, &end) {
> phys_addr_t size = end - start;
> - if (!total_mem)
> + if (!mem_start)
> mem_start = start;
> if (start <= vmlinux_start && vmlinux_end <= end)
> BUG_ON(size == 0);
> - total_mem = total_mem + 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);
This is on fixes. Thanks!
^ permalink raw reply [flat|nested] 2+ messages in thread
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