| Message ID | 20240403083611.172833-1-aneesh.kumar@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 5ca096161cdccfa328acf6704a4615528471d309 |
| Headers | show |
| Series | [1/3] powerpc/mm: Align memory_limit value specified using mem= kernel parameter | expand |
Acked-by: Joel Savitz <jsavitz@redhat.com>
On Wed, Apr 17, 2024 at 10:36 AM Joel Savitz <jsavitz@redhat.com> wrote: > > Acked-by: Joel Savitz <jsavitz@redhat.com> > Hi, What is the status of this? This patch fixes a bug where a powerpc machine hangs at boot when passed an unaligned value in the mem= kernel parameter. Best, Joel Savitz
Joel Savitz <jsavitz@redhat.com> writes: > On Wed, Apr 17, 2024 at 10:36 AM Joel Savitz <jsavitz@redhat.com> wrote: >> >> Acked-by: Joel Savitz <jsavitz@redhat.com> >> > > Hi, > > What is the status of this? This patch fixes a bug where a powerpc > machine hangs at boot when passed an unaligned value in the mem= > kernel parameter. It's in linux-next for v6.10 cheers
On Wed, 03 Apr 2024 14:06:09 +0530, Aneesh Kumar K.V (IBM) wrote: > The value specified for the memory limit is used to set a restriction on > memory usage. It is important to ensure that this restriction is within > the linear map kernel address space range. The hash page table > translation uses a 16MB page size to map the kernel linear map address > space. htab_bolt_mapping() function aligns down the size of the range > while mapping kernel linear address space. Since the memblock limit is > enforced very early during boot, before we can detect the type of memory > translation (radix vs hash), we align the memory limit value specified > as a kernel parameter to 16MB. This alignment value will work for both > hash and radix translations. > > [...] Applied to powerpc/next. [1/3] powerpc/mm: Align memory_limit value specified using mem= kernel parameter https://git.kernel.org/powerpc/c/5ca096161cdccfa328acf6704a4615528471d309 [2/3] powerpc/fadump: Don't update the user-specified memory limit https://git.kernel.org/powerpc/c/f94f5ac07983cb53de0c964f5428366c19e81993 [3/3] powerpc/mm: Update the memory limit based on direct mapping restrictions https://git.kernel.org/powerpc/c/5a799af9522641517f6d871d9f56e2658ee7db58 cheers
On Thu, May 2, 2024 at 10:20 PM Michael Ellerman <mpe@ellerman.id.au> wrote: > > Joel Savitz <jsavitz@redhat.com> writes: > > On Wed, Apr 17, 2024 at 10:36 AM Joel Savitz <jsavitz@redhat.com> wrote: > >> > >> Acked-by: Joel Savitz <jsavitz@redhat.com> > >> > > > > Hi, > > > > What is the status of this? This patch fixes a bug where a powerpc > > machine hangs at boot when passed an unaligned value in the mem= > > kernel parameter. > > It's in linux-next for v6.10 > > cheers > Thanks! Best, Joel Savitz
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index cd8d8883de90..7451bedad1f4 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -846,8 +846,11 @@ void __init early_init_devtree(void *params) reserve_crashkernel(); early_reserve_mem(); - /* Ensure that total memory size is page-aligned. */ - limit = ALIGN(memory_limit ?: memblock_phys_mem_size(), PAGE_SIZE); + if (memory_limit > memblock_phys_mem_size()) + memory_limit = 0; + + /* Align down to 16 MB which is large page size with hash page translation */ + limit = ALIGN_DOWN(memory_limit ?: memblock_phys_mem_size(), SZ_16M); memblock_enforce_memory_limit(limit); #if defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_PPC_4K_PAGES) diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c index 0ef358285337..fbb68fc28ed3 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -817,8 +817,8 @@ static void __init early_cmdline_parse(void) opt += 4; prom_memory_limit = prom_memparse(opt, (const char **)&opt); #ifdef CONFIG_PPC64 - /* Align to 16 MB == size of ppc64 large page */ - prom_memory_limit = ALIGN(prom_memory_limit, 0x1000000); + /* Align down to 16 MB which is large page size with hash page translation */ + prom_memory_limit = ALIGN_DOWN(prom_memory_limit, SZ_16M); #endif }
The value specified for the memory limit is used to set a restriction on memory usage. It is important to ensure that this restriction is within the linear map kernel address space range. The hash page table translation uses a 16MB page size to map the kernel linear map address space. htab_bolt_mapping() function aligns down the size of the range while mapping kernel linear address space. Since the memblock limit is enforced very early during boot, before we can detect the type of memory translation (radix vs hash), we align the memory limit value specified as a kernel parameter to 16MB. This alignment value will work for both hash and radix translations. Signed-off-by: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> --- arch/powerpc/kernel/prom.c | 7 +++++-- arch/powerpc/kernel/prom_init.c | 4 ++-- 2 files changed, 7 insertions(+), 4 deletions(-) base-commit: 3e92c1e6cd876754b64d1998ec0a01800ed954a6