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Date:      Thu, 12 Jun 2025 18:02:58 GMT
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org
Subject:   git: cb089f00996c - stable/14 - amd64: add pcb_tlsbase
Message-ID:  <202506121802.55CI2wVP066999@gitrepo.freebsd.org>

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The branch stable/14 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=cb089f00996cdbf2e7930b4e5598fcbbd43aae53

commit cb089f00996cdbf2e7930b4e5598fcbbd43aae53
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2025-05-19 23:56:37 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2025-06-12 18:02:49 +0000

    amd64: add pcb_tlsbase
    
    (cherry picked from commit 68ba38dad388b566877ba79ff02ed12a53b0ff3f)
---
 sys/amd64/amd64/exec_machdep.c     |  6 ++++--
 sys/amd64/amd64/sys_machdep.c      | 17 ++++++++++++++++-
 sys/amd64/amd64/vm_machdep.c       |  8 ++++----
 sys/amd64/ia32/ia32_signal.c       |  1 +
 sys/amd64/include/pcb.h            |  4 +++-
 sys/amd64/linux/linux_sysvec.c     |  2 +-
 sys/amd64/linux32/linux32_sysvec.c |  7 ++++---
 sys/x86/include/sysarch.h          |  2 ++
 8 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/sys/amd64/amd64/exec_machdep.c b/sys/amd64/amd64/exec_machdep.c
index cf635d822300..71e33e5b14c1 100644
--- a/sys/amd64/amd64/exec_machdep.c
+++ b/sys/amd64/amd64/exec_machdep.c
@@ -211,6 +211,8 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	regs->tf_fs = _ufssel;
 	regs->tf_gs = _ugssel;
 	regs->tf_flags = TF_HASSEGS;
+	if ((pcb->pcb_flags & PCB_TLSBASE) != 0)
+		pcb->pcb_fsbase = pcb->pcb_tlsbase;
 	PROC_LOCK(p);
 	mtx_lock(&psp->ps_mtx);
 }
@@ -381,9 +383,9 @@ exec_setregs(struct thread *td, struct image_params *imgp, uintptr_t stack)
 		user_ldt_free(td);
 
 	update_pcb_bases(pcb);
-	pcb->pcb_fsbase = 0;
+	pcb->pcb_fsbase = pcb->pcb_tlsbase = 0;
 	pcb->pcb_gsbase = 0;
-	clear_pcb_flags(pcb, PCB_32BIT);
+	clear_pcb_flags(pcb, PCB_32BIT | PCB_TLSBASE);
 	pcb->pcb_initial_fpucw = __INITIAL_FPUCW__;
 
 	saved_rflags = regs->tf_rflags & PSL_T;
diff --git a/sys/amd64/amd64/sys_machdep.c b/sys/amd64/amd64/sys_machdep.c
index 39c89e2aad87..2acf410b9b1b 100644
--- a/sys/amd64/amd64/sys_machdep.c
+++ b/sys/amd64/amd64/sys_machdep.c
@@ -208,6 +208,8 @@ sysarch(struct thread *td, struct sysarch_args *uap)
 	case AMD64_GET_XFPUSTATE:
 	case AMD64_SET_PKRU:
 	case AMD64_CLEAR_PKRU:
+	case AMD64_GET_TLSBASE:
+	case AMD64_SET_TLSBASE:
 		break;
 
 	case I386_SET_IOPERM:
@@ -313,14 +315,27 @@ sysarch(struct thread *td, struct sysarch_args *uap)
 		error = copyout(&pcb->pcb_fsbase, uap->parms,
 		    sizeof(pcb->pcb_fsbase));
 		break;
-		
+	case AMD64_GET_TLSBASE:
+		if ((pcb->pcb_flags & PCB_TLSBASE) == 0) {
+			error = ESRCH;
+		} else {
+			error = copyout(&pcb->pcb_tlsbase, uap->parms,
+			    sizeof(pcb->pcb_tlsbase));
+		}
+		break;
+
 	case AMD64_SET_FSBASE:
+	case AMD64_SET_TLSBASE:
 		error = copyin(uap->parms, &a64base, sizeof(a64base));
 		if (error == 0) {
 			if (a64base < curproc->p_sysent->sv_maxuser) {
 				set_pcb_flags(pcb, PCB_FULL_IRET);
 				pcb->pcb_fsbase = a64base;
 				td->td_frame->tf_fs = _ufssel;
+				if (uap->op == AMD64_SET_TLSBASE) {
+					pcb->pcb_tlsbase = a64base;
+					set_pcb_flags(pcb, PCB_TLSBASE);
+				}
 			} else
 				error = EINVAL;
 		}
diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c
index 36001bc5b5b6..8a2705a38c46 100644
--- a/sys/amd64/amd64/vm_machdep.c
+++ b/sys/amd64/amd64/vm_machdep.c
@@ -158,7 +158,7 @@ copy_thread(struct thread *td1, struct thread *td2)
 
 	/* Kernel threads start with clean FPU and segment bases. */
 	if ((td2->td_pflags & TDP_KTHREAD) != 0) {
-		pcb2->pcb_fsbase = 0;
+		pcb2->pcb_fsbase = pcb2->pcb_tlsbase = 0;
 		pcb2->pcb_gsbase = 0;
 		clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE |
 		    PCB_KERNFPU | PCB_KERNFPU_THR);
@@ -184,7 +184,7 @@ copy_thread(struct thread *td1, struct thread *td2)
 	 * pcb2->pcb_savefpu:	cloned above.
 	 * pcb2->pcb_flags:	cloned above.
 	 * pcb2->pcb_onfault:	cloned above (always NULL here?).
-	 * pcb2->pcb_[fg]sbase:	cloned above
+	 * pcb2->pcb_[f,g,tls]sbase:	cloned above
 	 */
 
 	pcb2->pcb_tssp = NULL;
@@ -675,13 +675,13 @@ cpu_set_user_tls(struct thread *td, void *tls_base)
 		return (EINVAL);
 
 	pcb = td->td_pcb;
-	set_pcb_flags(pcb, PCB_FULL_IRET);
+	set_pcb_flags(pcb, PCB_FULL_IRET | PCB_TLSBASE);
 #ifdef COMPAT_FREEBSD32
 	if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
 		pcb->pcb_gsbase = (register_t)tls_base;
 		return (0);
 	}
 #endif
-	pcb->pcb_fsbase = (register_t)tls_base;
+	pcb->pcb_fsbase = pcb->pcb_tlsbase = (register_t)tls_base;
 	return (0);
 }
diff --git a/sys/amd64/ia32/ia32_signal.c b/sys/amd64/ia32/ia32_signal.c
index b793c66a95ad..08f8d73c2334 100644
--- a/sys/amd64/ia32/ia32_signal.c
+++ b/sys/amd64/ia32/ia32_signal.c
@@ -959,4 +959,5 @@ ia32_setregs(struct thread *td, struct image_params *imgp, uintptr_t stack)
 
 	/* Return via doreti so that we can change to a different %cs */
 	set_pcb_flags(pcb, PCB_32BIT | PCB_FULL_IRET);
+	clear_pcb_flags(pcb, PCB_TLSBASE);
 }
diff --git a/sys/amd64/include/pcb.h b/sys/amd64/include/pcb.h
index 2205607fa6fe..632181c1f75a 100644
--- a/sys/amd64/include/pcb.h
+++ b/sys/amd64/include/pcb.h
@@ -86,6 +86,7 @@ struct pcb {
 #define	PCB_KERNFPU_THR	0x0020	/* fpu_kern_thread() */
 #define	PCB_32BIT	0x0040	/* process has 32 bit context (segs etc) */
 #define	PCB_FPUNOSAVE	0x0080	/* no save area for current FPU ctx */
+#define	PCB_TLSBASE	0x0100	/* tlsbase was set */
 
 	uint16_t	pcb_initial_fpucw;
 
@@ -106,7 +107,8 @@ struct pcb {
 
 	struct savefpu	*pcb_save;
 
-	uint64_t	pcb_pad[5];
+	register_t	pcb_tlsbase;	/* not same as pcb_fsbase */
+	uint64_t	pcb_pad[4];
 };
 
 /* Per-CPU state saved during suspend and resume. */
diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c
index 9c3d7e6405c1..3760a5455a73 100644
--- a/sys/amd64/linux/linux_sysvec.c
+++ b/sys/amd64/linux/linux_sysvec.c
@@ -247,7 +247,7 @@ linux_exec_setregs(struct thread *td, struct image_params *imgp,
 
 	pcb->pcb_fsbase = 0;
 	pcb->pcb_gsbase = 0;
-	clear_pcb_flags(pcb, PCB_32BIT);
+	clear_pcb_flags(pcb, PCB_32BIT | PCB_TLSBASE);
 	pcb->pcb_initial_fpucw = __LINUX_NPXCW__;
 	set_pcb_flags(pcb, PCB_FULL_IRET);
 
diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
index 19b4af7661f0..a8cc03ea8c71 100644
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -580,6 +580,10 @@ linux_exec_setregs(struct thread *td, struct image_params *imgp,
 	if (td->td_proc->p_md.md_ldt != NULL)
 		user_ldt_free(td);
 
+	/* Do full restore on return so that we can change to a different %cs */
+	set_pcb_flags(pcb, PCB_32BIT | PCB_FULL_IRET);
+	clear_pcb_flags(pcb, PCB_TLSBASE);
+
 	critical_enter();
 	wrmsr(MSR_FSBASE, 0);
 	wrmsr(MSR_KGSBASE, 0);	/* User value while we're in the kernel */
@@ -605,9 +609,6 @@ linux_exec_setregs(struct thread *td, struct image_params *imgp,
 	x86_clear_dbregs(pcb);
 
 	fpstate_drop(td);
-
-	/* Do full restore on return so that we can change to a different %cs */
-	set_pcb_flags(pcb, PCB_32BIT | PCB_FULL_IRET);
 }
 
 /*
diff --git a/sys/x86/include/sysarch.h b/sys/x86/include/sysarch.h
index 3226f3b9d93a..61f559f4bd23 100644
--- a/sys/x86/include/sysarch.h
+++ b/sys/x86/include/sysarch.h
@@ -61,6 +61,8 @@
 #define	AMD64_GET_XFPUSTATE	132
 #define	AMD64_SET_PKRU		133
 #define	AMD64_CLEAR_PKRU	134
+#define	AMD64_GET_TLSBASE	135
+#define	AMD64_SET_TLSBASE	136
 
 /* Flags for AMD64_SET_PKRU */
 #define	AMD64_PKRU_EXCL		0x0001



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