src/sys/amd64/include, branch main

amd64: add prototype for ia32_syscall()

2026-03-20T22:48:42Z

Sponsored by: The FreeBSD Foundation MFC after: 1 week

amd64: Make start_all_aps() static

2026-03-12T04:24:59Z

It is not used elsewhere since the change [1]. [1] ac3ede5371af x86/xen: remove PVHv1 code MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D55668

hwpmc: Remove left over k7, xscale and p4 references pmc

2026-03-07T15:17:43Z

Support for these processors was removed a few years ago, but a few references remain that should be removed. Sponsored by: Netflix Reviewed by: imp Pull Request: https://github.com/freebsd/freebsd-src/pull/2039

hwpmc: Initial support for AMD IBS

2026-02-27T21:22:16Z

This patch adds support for AMD IBS. It adds a new class of performance counter that cotains two events: ibs-fetch and ibs-op events. Unlike most existing sampled events, IBS events provide a number of values containing extra information regarding the sample. To support this we use the existing callchain event, and introduce a new flag for multipart payloads. The first 8 bytes of the pc_sample contains a header that defines up to four payloads. Sponsored by: Netflix Reviewed by: imp,mhorne Pull Request: https://github.com/freebsd/freebsd-src/pull/2022

i386,amd64: Explicitly set ECX=0 in do_cpuid() to be future-proof

2026-02-20T15:26:20Z

In principle, do_cpuid() should only be used for CPUID leaves without sub-leaves. Even accessing sub-leaf zero (ECX=0), one must use cpuid_count(ax, 0) rather than cpuid(ax). However, one might assume do_cpuid(ax) is equivalent to cpuid_count(ax, 0), but the old do_cpuid() did not initialize ECX before executing the CPUID instruction. If ECX contained a non-zero value, the instruction could return unexpected results, potentially leading to subtle and hard-to-debug issues, especially in ported code. To be future-proof and to help port code, adjust do_cpuid(ax) to be cpuid_count(ax, 0) to explicitly set ECX=0. It's believed that this change does not fix any real bugs in FreeBSD. See also the DragonFly commit: https://github.com/DragonFlyBSD/DragonFlyBSD/commit/0087a1d163488a57787a9a6431dd94070b1988d4 Signed-off-by: Aaron LI Reviewed by: kib Pull Request: https://github.com/freebsd/freebsd-src/pull/2027

amd64: add LASS support

2026-02-11T16:04:30Z

In short, LASS enforces all kernel memory accesses to have bit 63 set to 1, and all userspace accesses have bit 63 set to 0. Violations of these rules cause #GP. There are natural loopholes, like SMAP with rflags.AC=1 allows kernel to access userspace. Enablement is simple, we need to set CR4.LASS bit on all CPUs. There are complications when kernel has to execute code at low addresses, e.g. for la57 trampoline, or calling into EFI RT. The patch turns CR4.LASS off around these regions. LASS is officially documented in SDM, since at least rev. 085, October 2024. Tested in simics. Reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D55218

Revert "pcb.h: mark struct pcb to be preserved"

2026-02-09T18:55:57Z

kgdb only uses the marked fields from dumppcb for initial frame reconstruction. This reverts commit 8f23665fed2fbaf4481359b4d2fcdd7b9feb40e3.

amd64: define and use STACKALIGN and REDZONE_SZ

2026-02-09T17:57:00Z

Reviewed by: brooks, emaste, jhb Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D55151

pcb.h: mark struct pcb to be preserved

2026-02-09T04:17:16Z

There are programs that depend on this structure (e.g. kernel debuggers) that breaks when the ABI changes. Signed-off-by: Minsoo Choo Reviewed by: kib MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D55149

amd64: Fix sys/pcpu.h usage in vmm_host.h and md_var.h

2026-01-24T01:29:45Z

Include sys/pcpu in vmm_host.h as its structs and functions are used there, and add a forward declaration of struct pcpu to md_var.h as it is used in some function prototypes. Reviewed by: corvink, markj MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D51550