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    Subject[RFC PATCH v2 14/32] x86/fred: header file with FRED definitions
    Date
    From: "H. Peter Anvin (Intel)" <hpa@zytor.com>

    Add a header file for FRED prototypes and definitions.

    Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
    Signed-off-by: Xin Li <xin3.li@intel.com>
    ---
    arch/x86/include/asm/fred.h | 101 ++++++++++++++++++++++++++++++++++++
    1 file changed, 101 insertions(+)
    create mode 100644 arch/x86/include/asm/fred.h

    diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h
    new file mode 100644
    index 000000000000..f4de2cdd1c7f
    --- /dev/null
    +++ b/arch/x86/include/asm/fred.h
    @@ -0,0 +1,101 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +/*
    + * arch/x86/include/asm/fred.h
    + *
    + * Macros for Flexible Return and Event Delivery (FRED)
    + */
    +
    +#ifndef ASM_X86_FRED_H
    +#define ASM_X86_FRED_H
    +
    +#ifdef CONFIG_X86_FRED
    +
    +#include <linux/const.h>
    +#include <asm/asm.h>
    +
    +/*
    + * FRED return instructions
    + *
    + * Replace with "ERETS"/"ERETU" once binutils support FRED return instructions.
    + * The binutils version supporting FRED instructions is still TBD, and will
    + * update once we have it.
    + */
    +#define ERETS _ASM_BYTES(0xf2,0x0f,0x01,0xca)
    +#define ERETU _ASM_BYTES(0xf3,0x0f,0x01,0xca)
    +
    +/*
    + * Event stack level macro for the FRED_STKLVLS MSR.
    + * Usage example: FRED_STKLVL(X86_TRAP_DF, 3)
    + * Multiple values can be ORd together.
    + */
    +#define FRED_STKLVL(v,l) (_AT(unsigned long, l) << (2*(v)))
    +
    +/* FRED_CONFIG MSR */
    +#define FRED_CONFIG_CSL_MASK 0x3
    +#define FRED_CONFIG_SHADOW_STACK_SPACE _BITUL(3)
    +#define FRED_CONFIG_REDZONE(b) __ALIGN_KERNEL_MASK((b), _UL(0x3f))
    +#define FRED_CONFIG_INT_STKLVL(l) (_AT(unsigned long, l) << 9)
    +#define FRED_CONFIG_ENTRYPOINT(p) _AT(unsigned long, (p))
    +
    +/* FRED event type and vector bit width and counts */
    +#define FRED_EVENT_TYPE_BITS 3 /* only 3 bits used in FRED 3.0 */
    +#define FRED_EVENT_TYPE_COUNT _BITUL(FRED_EVENT_TYPE_BITS)
    +#define FRED_EVENT_VECTOR_BITS 8
    +#define FRED_EVENT_VECTOR_COUNT _BITUL(FRED_EVENT_VECTOR_BITS)
    +
    +/* FRED EVENT_TYPE_OTHER vector numbers */
    +#define FRED_SYSCALL 1
    +#define FRED_SYSENTER 2
    +
    +/* Flags above the CS selector (regs->csl) */
    +#define FRED_CSL_ENABLE_NMI _BITUL(28)
    +#define FRED_CSL_ALLOW_SINGLE_STEP _BITUL(25)
    +#define FRED_CSL_INTERRUPT_SHADOW _BITUL(24)
    +
    +#ifndef __ASSEMBLY__
    +
    +#include <linux/kernel.h>
    +#include <asm/ptrace.h>
    +
    +/* FRED stack frame information */
    +struct fred_info {
    + unsigned long edata; /* Event data: CR2, DR6, ... */
    + unsigned long resv;
    +};
    +
    +/* Full format of the FRED stack frame */
    +struct fred_frame {
    + struct pt_regs regs;
    + struct fred_info info;
    +};
    +
    +/* Getting the FRED frame information from a pt_regs pointer */
    +static __always_inline struct fred_info *fred_info(struct pt_regs *regs)
    +{
    + return &container_of(regs, struct fred_frame, regs)->info;
    +}
    +
    +static __always_inline unsigned long fred_event_data(struct pt_regs *regs)
    +{
    + return fred_info(regs)->edata;
    +}
    +
    +/*
    + * How FRED event handlers are called.
    + *
    + * FRED event delivery establishes the full supervisor context
    + * by pushing everything related to the event being delivered
    + * to the FRED stack frame, e.g., the faulting linear address
    + * of a #PF is pushed as event data of the FRED #PF stack frame.
    + * Thus a struct pt_regs has everything needed and it's the only
    + * input parameter required for a FRED event handler.
    + */
    +#define DECLARE_FRED_HANDLER(f) void f (struct pt_regs *regs)
    +#define DEFINE_FRED_HANDLER(f) noinstr DECLARE_FRED_HANDLER(f)
    +typedef DECLARE_FRED_HANDLER((*fred_handler));
    +
    +#endif /* __ASSEMBLY__ */
    +
    +#endif /* CONFIG_X86_FRED */
    +
    +#endif /* ASM_X86_FRED_H */
    --
    2.34.1
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