Messages in this thread | | | From | Christophe Leroy <> | Subject | Re: [PATCH] powerpc: align memory_limit to 16MB in early_parse_mem | Date | Wed, 10 Apr 2024 15:31:15 +0000 |
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Le 10/04/2024 à 17:22, Joel Savitz a écrit : > [Vous ne recevez pas souvent de courriers de jsavitz@redhat.com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ] > > On Mon, Apr 1, 2024 at 10:17 AM Joel Savitz <jsavitz@redhat.com> wrote: >> >> On Tue, Mar 26, 2024 at 12:45 AM Joel Savitz <jsavitz@redhat.com> wrote: >>> >>> On Fri, Mar 8, 2024 at 5:18 AM Aneesh Kumar K.V <aneesh.kumar@kernel.org> wrote: >>>> >>>> Joel Savitz <jsavitz@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 <gsierohu@redhat.com> >>>>> Signed-off-by: Gonzalo Siero <gsierohu@redhat.com> >>>>> Signed-off-by: Joel Savitz <jsavitz@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.kumar@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.kumar@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.kumar@kernel.org/ ?
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