From 2d7bc823503167276c6d3c40500c3055d4f38938 Mon Sep 17 00:00:00 2001 From: Ian Moffett Date: Tue, 2 Jul 2024 21:19:49 -0400 Subject: kernel/amd64: Handle the user GS segment register This commit introduces usage of swapgs to switch out the GS register with the user GS register. An md_td_kick() function is also introduced to start up user threads. The this_cpu() function uses the GS register to read the current CPU structure using a new "self" field. Signed-off-by: Ian Moffett --- sys/include/arch/amd64/cpu.h | 1 + sys/include/arch/amd64/frameasm.h | 24 ++++++++++++++++++++---- 2 files changed, 21 insertions(+), 4 deletions(-) (limited to 'sys/include/arch/amd64') diff --git a/sys/include/arch/amd64/cpu.h b/sys/include/arch/amd64/cpu.h index 16936e9..2ce363c 100644 --- a/sys/include/arch/amd64/cpu.h +++ b/sys/include/arch/amd64/cpu.h @@ -42,6 +42,7 @@ struct cpu_info { size_t lapic_tmr_freq; struct tss_entry *tss; struct proc *curtd; + struct cpu_info *self; }; void cpu_startup(struct cpu_info *ci); diff --git a/sys/include/arch/amd64/frameasm.h b/sys/include/arch/amd64/frameasm.h index b8791ba..8983d36 100644 --- a/sys/include/arch/amd64/frameasm.h +++ b/sys/include/arch/amd64/frameasm.h @@ -106,11 +106,19 @@ */ #define INTRENTRY(ENTLABEL, HANDLER) \ ENTLABEL: \ - push_trapframe $0 ; \ + testq $0x3, 8(%rsp) ; \ + jz 1f ; \ + lfence ; \ + swapgs ; \ + 1: push_trapframe $0 ; \ mov %rsp, %rdi ; \ call HANDLER ; \ pop_trapframe ; \ - iretq + testq $0x3, 8(%rsp) ; \ + jz 2f ; \ + lfence ; \ + swapgs ; \ + 2: iretq /* * Trap entry where an error code is on @@ -118,10 +126,18 @@ */ #define TRAPENTRY(ENTLABEL, TRAPNO) \ ENTLABEL: \ - push_trapframe_ec TRAPNO ; \ + testq $0x3, 8(%rsp) ; \ + jz 1f ; \ + lfence ; \ + swapgs ; \ + 1: push_trapframe_ec TRAPNO ; \ mov %rsp, %rdi ; \ call trap_handler ; \ pop_trapframe_ec ; \ - iretq + testq $0x3, 8(%rsp) ; \ + jz 2f ; \ + lfence ; \ + swapgs ; \ + 2: iretq #endif /* !_MACHINE_FRAMEASM_H_ */ -- cgit v1.2.3