From 3841840449817ba6cf3e636008bc4e1061a03388 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Tue, 20 Nov 2018 08:25:28 +0100 Subject: x86/boot: Mostly revert commit ae7e1238e68f2a ("Add ACPI RSDP address to setup_header") Peter Anvin pointed out that commit: ae7e1238e68f2a ("x86/boot: Add ACPI RSDP address to setup_header") should be reverted as setup_header should only contain items set by the legacy BIOS. So revert said commit. Instead of fully reverting the dependent commit of: e7b66d16fe4172 ("x86/acpi, x86/boot: Take RSDP address for boot params if available") just remove the setup_header reference in order to replace it by a boot_params in a followup patch. Suggested-by: "H. Peter Anvin" Signed-off-by: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boris.ostrovsky@oracle.com Cc: bp@alien8.de Cc: daniel.kiper@oracle.com Cc: sstabellini@kernel.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181120072529.5489-2-jgross@suse.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/acpi/boot.c | 2 +- arch/x86/kernel/head32.c | 1 - arch/x86/kernel/head64.c | 2 -- arch/x86/kernel/setup.c | 17 ----------------- 4 files changed, 1 insertion(+), 21 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 92c76bf97ad8..fb3b1f3a5aba 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -1776,5 +1776,5 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size) u64 x86_default_get_root_pointer(void) { - return boot_params.hdr.acpi_rsdp_addr; + return 0; } diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c index 76fa3b836598..ec6fefbfd3c0 100644 --- a/arch/x86/kernel/head32.c +++ b/arch/x86/kernel/head32.c @@ -37,7 +37,6 @@ asmlinkage __visible void __init i386_start_kernel(void) cr4_init_shadow(); sanitize_boot_params(&boot_params); - x86_verify_bootdata_version(); x86_early_init_platform_quirks(); diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 7663a8eb602b..16b1cbd3a61e 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -457,8 +457,6 @@ void __init x86_64_start_reservations(char *real_mode_data) if (!boot_params.hdr.version) copy_bootdata(__va(real_mode_data)); - x86_verify_bootdata_version(); - x86_early_init_platform_quirks(); switch (boot_params.hdr.hardware_subarch) { diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index b74e7bfed6ab..d494b9bfe618 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1280,23 +1280,6 @@ void __init setup_arch(char **cmdline_p) unwind_init(); } -/* - * From boot protocol 2.14 onwards we expect the bootloader to set the - * version to "0x8000 | ". In case we find a version >= 2.14 - * without the 0x8000 we assume the boot loader supports 2.13 only and - * reset the version accordingly. The 0x8000 flag is removed in any case. - */ -void __init x86_verify_bootdata_version(void) -{ - if (boot_params.hdr.version & VERSION_WRITTEN) - boot_params.hdr.version &= ~VERSION_WRITTEN; - else if (boot_params.hdr.version >= 0x020e) - boot_params.hdr.version = 0x020d; - - if (boot_params.hdr.version < 0x020e) - boot_params.hdr.acpi_rsdp_addr = 0; -} - #ifdef CONFIG_X86_32 static struct resource video_ram_resource = { -- cgit v1.2.2 From e6e094e053af75cbc164e950814d3d084fb1e698 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Tue, 20 Nov 2018 08:25:29 +0100 Subject: x86/acpi, x86/boot: Take RSDP address from boot params if available In case the RSDP address in struct boot_params is specified don't try to find the table by searching, but take the address directly as set by the boot loader. Suggested-by: "H. Peter Anvin" Signed-off-by: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boris.ostrovsky@oracle.com Cc: bp@alien8.de Cc: daniel.kiper@oracle.com Cc: sstabellini@kernel.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181120072529.5489-3-jgross@suse.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/acpi/boot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index fb3b1f3a5aba..06635fbca81c 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -1776,5 +1776,5 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size) u64 x86_default_get_root_pointer(void) { - return 0; + return boot_params.acpi_rsdp_addr; } -- cgit v1.2.2 From 68239654acafe6aad5a3c1dc7237e60accfebc03 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Tue, 20 Nov 2018 11:26:35 +0100 Subject: x86/fpu: Disable bottom halves while loading FPU registers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The sequence fpu->initialized = 1; /* step A */ preempt_disable(); /* step B */ fpu__restore(fpu); preempt_enable(); in __fpu__restore_sig() is racy in regard to a context switch. For 32bit frames, __fpu__restore_sig() prepares the FPU state within fpu->state. To ensure that a context switch (switch_fpu_prepare() in particular) does not modify fpu->state it uses fpu__drop() which sets fpu->initialized to 0. After fpu->initialized is cleared, the CPU's FPU state is not saved to fpu->state during a context switch. The new state is loaded via fpu__restore(). It gets loaded into fpu->state from userland and ensured it is sane. fpu->initialized is then set to 1 in order to avoid fpu__initialize() doing anything (overwrite the new state) which is part of fpu__restore(). A context switch between step A and B above would save CPU's current FPU registers to fpu->state and overwrite the newly prepared state. This looks like a tiny race window but the Kernel Test Robot reported this back in 2016 while we had lazy FPU support. Borislav Petkov made the link between that report and another patch that has been posted. Since the removal of the lazy FPU support, this race goes unnoticed because the warning has been removed. Disable bottom halves around the restore sequence to avoid the race. BH need to be disabled because BH is allowed to run (even with preemption disabled) and might invoke kernel_fpu_begin() by doing IPsec. [ bp: massage commit message a bit. ] Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Borislav Petkov Acked-by: Ingo Molnar Acked-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: "Jason A. Donenfeld" Cc: kvm ML Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Rik van Riel Cc: stable@vger.kernel.org Cc: x86-ml Link: http://lkml.kernel.org/r/20181120102635.ddv3fvavxajjlfqk@linutronix.de Link: https://lkml.kernel.org/r/20160226074940.GA28911@pd.tnic --- arch/x86/kernel/fpu/signal.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 61a949d84dfa..d99a8ee9e185 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -344,10 +344,10 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) sanitize_restored_xstate(tsk, &env, xfeatures, fx_only); } + local_bh_disable(); fpu->initialized = 1; - preempt_disable(); fpu__restore(fpu); - preempt_enable(); + local_bh_enable(); return err; } else { -- cgit v1.2.2 From 60c8144afc287ef09ce8c1230c6aa972659ba1bb Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Tue, 27 Nov 2018 14:41:37 +0100 Subject: x86/MCE/AMD: Fix the thresholding machinery initialization order MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, the code sets up the thresholding interrupt vector and only then goes about initializing the thresholding banks. Which is wrong, because an early thresholding interrupt would cause a NULL pointer dereference when accessing those banks and prevent the machine from booting. Therefore, set the thresholding interrupt vector only *after* having initialized the banks successfully. Fixes: 18807ddb7f88 ("x86/mce/AMD: Reset Threshold Limit after logging error") Reported-by: Rafał Miłecki Reported-by: John Clemens Signed-off-by: Borislav Petkov Tested-by: Rafał Miłecki Tested-by: John Clemens Cc: Aravind Gopalakrishnan Cc: linux-edac@vger.kernel.org Cc: stable@vger.kernel.org Cc: Tony Luck Cc: x86@kernel.org Cc: Yazen Ghannam Link: https://lkml.kernel.org/r/20181127101700.2964-1-zajec5@gmail.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=201291 --- arch/x86/kernel/cpu/mcheck/mce_amd.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c index dd33c357548f..e12454e21b8a 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c @@ -56,7 +56,7 @@ /* Threshold LVT offset is at MSR0xC0000410[15:12] */ #define SMCA_THR_LVT_OFF 0xF000 -static bool thresholding_en; +static bool thresholding_irq_en; static const char * const th_names[] = { "load_store", @@ -534,9 +534,8 @@ prepare_threshold_block(unsigned int bank, unsigned int block, u32 addr, set_offset: offset = setup_APIC_mce_threshold(offset, new); - - if ((offset == new) && (mce_threshold_vector != amd_threshold_interrupt)) - mce_threshold_vector = amd_threshold_interrupt; + if (offset == new) + thresholding_irq_en = true; done: mce_threshold_block_init(&b, offset); @@ -1357,9 +1356,6 @@ int mce_threshold_remove_device(unsigned int cpu) { unsigned int bank; - if (!thresholding_en) - return 0; - for (bank = 0; bank < mca_cfg.banks; ++bank) { if (!(per_cpu(bank_map, cpu) & (1 << bank))) continue; @@ -1377,9 +1373,6 @@ int mce_threshold_create_device(unsigned int cpu) struct threshold_bank **bp; int err = 0; - if (!thresholding_en) - return 0; - bp = per_cpu(threshold_banks, cpu); if (bp) return 0; @@ -1408,9 +1401,6 @@ static __init int threshold_init_device(void) { unsigned lcpu = 0; - if (mce_threshold_vector == amd_threshold_interrupt) - thresholding_en = true; - /* to hit CPUs online before the notifier is up */ for_each_online_cpu(lcpu) { int err = mce_threshold_create_device(lcpu); @@ -1419,6 +1409,9 @@ static __init int threshold_init_device(void) return err; } + if (thresholding_irq_en) + mce_threshold_vector = amd_threshold_interrupt; + return 0; } /* -- cgit v1.2.2