On Wed, Apr 10, 2024 at 11:31 AM Christophe Leroy <christophe.le...@csgroup.eu> wrote: > > > > Le 10/04/2024 à 17:22, Joel Savitz a écrit : > > [Vous ne recevez pas souvent de courriers de jsav...@redhat.com. Découvrez > > pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification > > ] > > > > On Mon, Apr 1, 2024 at 10:17 AM Joel Savitz <jsav...@redhat.com> wrote: > >> > >> On Tue, Mar 26, 2024 at 12:45 AM Joel Savitz <jsav...@redhat.com> wrote: > >>> > >>> On Fri, Mar 8, 2024 at 5:18 AM Aneesh Kumar K.V <aneesh.ku...@kernel.org> > >>> wrote: > >>>> > >>>> Joel Savitz <jsav...@redhat.com> writes: > >>>> > >>>>> On 64-bit powerpc, usage of a non-16MB-aligned value for the mem= kernel > >>>>> cmdline parameter results in a system hang at boot. > >>>>> > >>>>> For example, using 'mem=4198400K' will always reproduce this issue. > >>>>> > >>>>> This patch fixes the problem by aligning any argument to mem= to 16MB > >>>>> corresponding with the large page size on powerpc. > >>>>> > >>>>> Fixes: 2babf5c2ec2f ("[PATCH] powerpc: Unify mem= handling") > >>>>> Co-developed-by: Gonzalo Siero <gsier...@redhat.com> > >>>>> Signed-off-by: Gonzalo Siero <gsier...@redhat.com> > >>>>> Signed-off-by: Joel Savitz <jsav...@redhat.com> > >>>>> --- > >>>>> arch/powerpc/kernel/prom.c | 6 +++++- > >>>>> 1 file changed, 5 insertions(+), 1 deletion(-) > >>>>> > >>>>> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c > >>>>> index 0b5878c3125b..8cd3e2445d8a 100644 > >>>>> --- a/arch/powerpc/kernel/prom.c > >>>>> +++ b/arch/powerpc/kernel/prom.c > >>>>> @@ -82,8 +82,12 @@ static int __init early_parse_mem(char *p) > >>>>> { > >>>>> if (!p) > >>>>> return 1; > >>>>> - > >>>>> +#ifdef CONFIG_PPC64 > >>>>> + /* Align to 16 MB == size of ppc64 large page */ > >>>>> + memory_limit = ALIGN(memparse(p, &p), 0x1000000); > >>>>> +#else > >>>>> memory_limit = PAGE_ALIGN(memparse(p, &p)); > >>>>> +#endif > >>>>> DBG("memory limit = 0x%llx\n", memory_limit); > >>>>> > >>>>> return 0; > >>>>> -- > >>>>> 2.43.0 > >>>> > >>>> Can you try this change? > >>>> > >>>> commit 5555bc55e1aa71f545cff31e1eccdb4a2e39df84 > >>>> Author: Aneesh Kumar K.V (IBM) <aneesh.ku...@kernel.org> > >>>> Date: Fri Mar 8 14:45:26 2024 +0530 > >>>> > >>>> powerpc/mm: Align memory_limit value specified using mem= kernel > >>>> parameter > >>>> > >>>> 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.ku...@kernel.org> > >>>> > >>>> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c > >>>> index 0b5878c3125b..9bd965d35352 100644 > >>>> --- a/arch/powerpc/kernel/prom.c > >>>> +++ b/arch/powerpc/kernel/prom.c > >>>> @@ -824,8 +824,11 @@ 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 e67effdba85c..d6410549e141 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 > >>>> } > >>>> > >>>> > >>> > >>> Sorry for the delayed reply. I just tested this patch and it fixes the > >>> bug for me. > >> > >> Hi, > >> > >> Just a quick follow up on this. > >> > >> The above patch fixed the bug for me. > >> > >> How do we want to proceed? > >> > >> Best, > >> Joel Savitz > > > > Hi, > > > > I haven't heard anything on this thread so I'm just sending a quick follow > > up. > > > > Do we want to merge this > > > > Is it the same as > https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20240403083611.172833-1-aneesh.ku...@kernel.org/ > ?
Yes that appears to be the case.
