The following commit has been merged into the x86/fred branch of tip:
Commit-ID: 73270c1f2369fb37683121ebe097cd37172602b6
Gitweb: https://git.kernel.org/tip/73270c1f2369fb37683121ebe097cd37172602b6
Author: Xin Li (Intel) <xin@xxxxxxxxx>
AuthorDate: Tue, 09 Jul 2024 08:40:47 -07:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 13 Aug 2024 21:59:21 +02:00
x86/fred: Move FRED RSP initialization into a separate function
To enable FRED earlier, move the RSP initialization out of
cpu_init_fred_exceptions() into cpu_init_fred_rsps().
This is required as the FRED RSP initialization depends on the availability
of the CPU entry areas which are set up late in trap_init(),
No functional change intended. Marked with Fixes as it's a depedency for
the real fix.
Fixes: 14619d912b65 ("x86/fred: FRED entry/exit and dispatch code")
Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20240709154048.3543361-3-xin@xxxxxxxxx
---
arch/x86/include/asm/fred.h | 2 ++
arch/x86/kernel/cpu/common.c | 6 ++++--
arch/x86/kernel/fred.c | 28 +++++++++++++++++++---------
3 files changed, 25 insertions(+), 11 deletions(-)
diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h
index e86c7ba..66d7dbe 100644
--- a/arch/x86/include/asm/fred.h
+++ b/arch/x86/include/asm/fred.h
@@ -84,11 +84,13 @@ static __always_inline void fred_entry_from_kvm(unsigned int type, unsigned int
}
void cpu_init_fred_exceptions(void);
+void cpu_init_fred_rsps(void);
void fred_complete_exception_setup(void);
#else /* CONFIG_X86_FRED */
static __always_inline unsigned long fred_event_data(struct pt_regs *regs) { return 0; }
static inline void cpu_init_fred_exceptions(void) { }
+static inline void cpu_init_fred_rsps(void) { }
static inline void fred_complete_exception_setup(void) { }
static __always_inline void fred_entry_from_kvm(unsigned int type, unsigned int vector) { }
#endif /* CONFIG_X86_FRED */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 10a5402..6de12b3 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2195,10 +2195,12 @@ void cpu_init_exception_handling(void)
/* GHCB needs to be setup to handle #VC. */
setup_ghcb();
- if (cpu_feature_enabled(X86_FEATURE_FRED))
+ if (cpu_feature_enabled(X86_FEATURE_FRED)) {
cpu_init_fred_exceptions();
- else
+ cpu_init_fred_rsps();
+ } else {
load_current_idt();
+ }
}
/*
diff --git a/arch/x86/kernel/fred.c b/arch/x86/kernel/fred.c
index 4bcd879..99a134f 100644
--- a/arch/x86/kernel/fred.c
+++ b/arch/x86/kernel/fred.c
@@ -32,6 +32,25 @@ void cpu_init_fred_exceptions(void)
FRED_CONFIG_INT_STKLVL(0) |
FRED_CONFIG_ENTRYPOINT(asm_fred_entrypoint_user));
+ wrmsrl(MSR_IA32_FRED_STKLVLS, 0);
+ wrmsrl(MSR_IA32_FRED_RSP0, 0);
+ wrmsrl(MSR_IA32_FRED_RSP1, 0);
+ wrmsrl(MSR_IA32_FRED_RSP2, 0);
+ wrmsrl(MSR_IA32_FRED_RSP3, 0);
+
+ /* Enable FRED */
+ cr4_set_bits(X86_CR4_FRED);
+ /* Any further IDT use is a bug */
+ idt_invalidate();
+
+ /* Use int $0x80 for 32-bit system calls in FRED mode */
+ setup_clear_cpu_cap(X86_FEATURE_SYSENTER32);
+ setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
+}
+
+/* Must be called after setup_cpu_entry_areas() */
+void cpu_init_fred_rsps(void)
+{
/*
* The purpose of separate stacks for NMI, #DB and #MC *in the kernel*
* (remember that user space faults are always taken on stack level 0)
@@ -47,13 +66,4 @@ void cpu_init_fred_exceptions(void)
wrmsrl(MSR_IA32_FRED_RSP1, __this_cpu_ist_top_va(DB));
wrmsrl(MSR_IA32_FRED_RSP2, __this_cpu_ist_top_va(NMI));
wrmsrl(MSR_IA32_FRED_RSP3, __this_cpu_ist_top_va(DF));
-
- /* Enable FRED */
- cr4_set_bits(X86_CR4_FRED);
- /* Any further IDT use is a bug */
- idt_invalidate();
-
- /* Use int $0x80 for 32-bit system calls in FRED mode */
- setup_clear_cpu_cap(X86_FEATURE_SYSENTER32);
- setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
}
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