From b0525e4b808ccfaa1017872c5902b504d4991e95 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 14 Feb 2019 09:49:25 -0500 Subject: ARM: split out processor lookup Commit 65987a8553061515b5851b472081aedb9837a391 upstream. Split out the lookup of the processor type and associated error handling from the rest of setup_processor() - we will need to use this in the secondary CPU bringup path for big.Little Spectre variant 2 mitigation. Reviewed-by: Julien Thierry Signed-off-by: Russell King Signed-off-by: David A. Long Reviewed-by: Julien Thierry Signed-off-by: Sasha Levin --- arch/arm/kernel/setup.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) (limited to 'arch/arm/kernel/setup.c') diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index f4e54503afa9..8d5c3a118abe 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -667,22 +667,29 @@ static void __init smp_build_mpidr_hash(void) } #endif -static void __init setup_processor(void) +/* + * locate processor in the list of supported processor types. The linker + * builds this table for us from the entries in arch/arm/mm/proc-*.S + */ +struct proc_info_list *lookup_processor(u32 midr) { - struct proc_info_list *list; + struct proc_info_list *list = lookup_processor_type(midr); - /* - * locate processor in the list of supported processor - * types. The linker builds this table for us from the - * entries in arch/arm/mm/proc-*.S - */ - list = lookup_processor_type(read_cpuid_id()); if (!list) { - pr_err("CPU configuration botched (ID %08x), unable to continue.\n", - read_cpuid_id()); - while (1); + pr_err("CPU%u: configuration botched (ID %08x), CPU halted\n", + smp_processor_id(), midr); + while (1) + /* can't use cpu_relax() here as it may require MMU setup */; } + return list; +} + +static void __init setup_processor(void) +{ + unsigned int midr = read_cpuid_id(); + struct proc_info_list *list = lookup_processor(midr); + cpu_name = list->cpu_name; __cpu_architecture = __get_cpu_architecture(); @@ -700,7 +707,7 @@ static void __init setup_processor(void) #endif pr_info("CPU: %s [%08x] revision %d (ARMv%s), cr=%08lx\n", - cpu_name, read_cpuid_id(), read_cpuid_id() & 15, + list->cpu_name, midr, midr & 15, proc_arch[cpu_architecture()], get_cr()); snprintf(init_utsname()->machine, __NEW_UTS_LEN + 1, "%s%c", -- cgit v1.2.3 From 2dbc7e3efe2ca2e9eb614c66ea725c2116103b56 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 14 Feb 2019 09:49:27 -0500 Subject: ARM: add PROC_VTABLE and PROC_TABLE macros Commit e209950fdd065d2cc46e6338e47e52841b830cba upstream. Allow the way we access members of the processor vtable to be changed at compile time. We will need to move to per-CPU vtables to fix the Spectre variant 2 issues on big.Little systems. However, we have a couple of calls that do not need the vtable treatment, and indeed cause a kernel warning due to the (later) use of smp_processor_id(), so also introduce the PROC_TABLE macro for these which always use CPU 0's function pointers. Reviewed-by: Julien Thierry Signed-off-by: Russell King Signed-off-by: David A. Long Reviewed-by: Julien Thierry Signed-off-by: Sasha Levin --- arch/arm/kernel/setup.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'arch/arm/kernel/setup.c') diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 8d5c3a118abe..2eebb67fa08b 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -693,9 +693,7 @@ static void __init setup_processor(void) cpu_name = list->cpu_name; __cpu_architecture = __get_cpu_architecture(); -#ifdef MULTI_CPU - processor = *list->proc; -#endif + init_proc_vtable(list->proc); #ifdef MULTI_TLB cpu_tlb = *list->tlb; #endif -- cgit v1.2.3 From ab6c39771d579350bcd9c46514831b05430bd51a Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 14 Feb 2019 09:49:28 -0500 Subject: ARM: spectre-v2: per-CPU vtables to work around big.Little systems Commit 383fb3ee8024d596f488d2dbaf45e572897acbdb upstream. In big.Little systems, some CPUs require the Spectre workarounds in paths such as the context switch, but other CPUs do not. In order to handle these differences, we need per-CPU vtables. We are unable to use the kernel's per-CPU variables to support this as per-CPU is not initialised at times when we need access to the vtables, so we have to use an array indexed by logical CPU number. We use an array-of-pointers to avoid having function pointers in the kernel's read/write .data section. Note: Added include of linux/slab.h in arch/arm/smp.c. Reviewed-by: Julien Thierry Signed-off-by: Russell King Signed-off-by: David A. Long Reviewed-by: Julien Thierry Signed-off-by: Sasha Levin --- arch/arm/kernel/setup.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/arm/kernel/setup.c') diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 2eebb67fa08b..4764742db7b0 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -115,6 +115,11 @@ EXPORT_SYMBOL(elf_hwcap2); #ifdef MULTI_CPU struct processor processor __ro_after_init; +#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR) +struct processor *cpu_vtable[NR_CPUS] = { + [0] = &processor, +}; +#endif #endif #ifdef MULTI_TLB struct cpu_tlb_fns cpu_tlb __ro_after_init; -- cgit v1.2.3