From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 98FAFCF8852 for ; Fri, 4 Oct 2024 23:38:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=5jRlSgp23qR0Cyzu9QHIiDtMBpvyeilzzyEhkpp7IwM=; b=TliZS0Ugd40SaZfznEQeC4aCmG Eg+ThJDgl/StZCb5MOKSokTGUJq2mUg+Qplty3UMvy62JlPHXnz24FxHVBqrTt5aP5wxjgdvzC+re OPLovtZahIQ6TWLxl7kZgmao4S/vpe/ZmA6es7VkmgcUr58LGI0y4hzpNtlUvWxTeK7MOj4NqYt0I cThBZr5qoZNV0tv87SkdXcIlI4aJRXFLA3COPTphzz0KF2Eet4AeVkp4gpKM+Bv/g/Pq7h0miIHz9 5e0oyCjHkgqz8FM2lv+WxgZbVi+60qb1k992mMLZvOR96FIuHHj+xAAKwY+MImvQwdS1UjapvUAfj XyISpa8w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1swrso-0000000ESqk-2jDB; Fri, 04 Oct 2024 23:38:50 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:242:246e::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1swrsf-0000000ESpP-1MOv for linux-um@lists.infradead.org; Fri, 04 Oct 2024 23:38:42 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=Content-Transfer-Encoding:MIME-Version: Message-ID:Date:Subject:Cc:To:From:Content-Type:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-To:Resent-Cc: Resent-Message-ID:In-Reply-To:References; bh=5jRlSgp23qR0Cyzu9QHIiDtMBpvyeilzzyEhkpp7IwM=; t=1728085120; x=1729294720; b=h3IdbFARcmiZzAmvb/iQ3koWolfjNFjdrNS5Ay6CnQf8pfsF5SHyl3UpOhqZLD+Z//OF2UV3DvJ Ux7NHcphj6rNVieUdDUdYIky77g1P/QE39ymo/eYsTmFBadPn78qDcHUT/26aRuDOSNbO+VyDuZsh yPwGuWsvhbMaV1T3VOS6VKbU4sLci2BFvst14Gqy9vDBUU3mbVYYZ2lUwdO5wx6/V6vQ3NxrVNBCa GI+gknRqBTwNRdp9Ge3iKzuLV4CO3JNjd2ig/D3Zl/ZcdhUDk9xekHZVZaEN6EiJ1txxRDuvj33GE vBI97WA8lOxtdcjGxzVdnhpZY/NLdLL4sX2g==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.98) (envelope-from ) id 1swrsb-00000000AkR-3Jcn; Sat, 05 Oct 2024 01:38:38 +0200 From: Benjamin Berg To: linux-um@lists.infradead.org Cc: Benjamin Berg Subject: [PATCH] um: remove auxiliary FP registers Date: Sat, 5 Oct 2024 01:38:21 +0200 Message-ID: <20241004233821.2130874-1-benjamin@sipsolutions.net> X-Mailer: git-send-email 2.46.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241004_163841_410201_D3BE9629 X-CRM114-Status: GOOD ( 14.95 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org From: Benjamin Berg We do not need the extra save/restore of the FP registers when getting the fault information. This was originally added in commit 2f56debd77a8 ("uml: fix FP register corruption") but at that time the code was not saving/restoring the FP registers when switching to userspace. This was fixed in commit fbfe9c847edf ("um: Save FPU registers between task switches") and since then the auxiliary registers have not been useful. Signed-off-by: Benjamin Berg --- arch/um/include/asm/thread_info.h | 2 -- arch/um/include/shared/os.h | 2 +- arch/um/kernel/process.c | 4 ++-- arch/um/os-Linux/skas/process.c | 25 ++++++------------------- 4 files changed, 9 insertions(+), 24 deletions(-) diff --git a/arch/um/include/asm/thread_info.h b/arch/um/include/asm/thread_info.h index c7b4b49826a2..4d2a768246bc 100644 --- a/arch/um/include/asm/thread_info.h +++ b/arch/um/include/asm/thread_info.h @@ -23,8 +23,6 @@ struct thread_info { int preempt_count; /* 0 => preemptable, <0 => BUG */ struct thread_info *real_thread; /* Points to non-IRQ stack */ - unsigned long aux_fp_regs[FP_SIZE]; /* auxiliary fp_regs to save/restore - them out-of-band */ }; #define INIT_THREAD_INFO(tsk) \ diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h index 33c4d2677591..bf539fee7831 100644 --- a/arch/um/include/shared/os.h +++ b/arch/um/include/shared/os.h @@ -285,7 +285,7 @@ int protect(struct mm_id *mm_idp, unsigned long addr, /* skas/process.c */ extern int is_skas_winch(int pid, int fd, void *data); extern int start_userspace(unsigned long stub_stack); -extern void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs); +extern void userspace(struct uml_pt_regs *regs); extern void new_thread(void *stack, jmp_buf *buf, void (*handler)(void)); extern void switch_threads(jmp_buf *me, jmp_buf *you); extern int start_idle_thread(void *stack, jmp_buf *switch_buf); diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c index 701b7bb2525e..d45c79f82d7c 100644 --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -116,7 +116,7 @@ void new_thread_handler(void) * callback returns only if the kernel thread execs a process */ fn(arg); - userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs); + userspace(¤t->thread.regs.regs); } /* Called magically, see new_thread_handler above */ @@ -133,7 +133,7 @@ static void fork_handler(void) current->thread.prev_sched = NULL; - userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs); + userspace(¤t->thread.regs.regs); } int copy_thread(struct task_struct * p, const struct kernel_clone_args *args) diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index 95376357fb17..ad2e45d80c98 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -144,16 +144,10 @@ void wait_stub_done(int pid) extern unsigned long current_stub_stack(void); -static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux_fp_regs) +static void get_skas_faultinfo(int pid, struct faultinfo *fi) { int err; - err = get_fp_registers(pid, aux_fp_regs); - if (err < 0) { - printk(UM_KERN_ERR "save_fp_registers returned %d\n", - err); - fatal_sigsegv(); - } err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV); if (err) { printk(UM_KERN_ERR "Failed to continue stub, pid = %d, " @@ -167,18 +161,11 @@ static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux * the stub stack page. We just have to copy it. */ memcpy(fi, (void *)current_stub_stack(), sizeof(*fi)); - - err = put_fp_registers(pid, aux_fp_regs); - if (err < 0) { - printk(UM_KERN_ERR "put_fp_registers returned %d\n", - err); - fatal_sigsegv(); - } } -static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp_regs) +static void handle_segv(int pid, struct uml_pt_regs *regs) { - get_skas_faultinfo(pid, ®s->faultinfo, aux_fp_regs); + get_skas_faultinfo(pid, ®s->faultinfo); segv(regs->faultinfo, 0, 1, NULL); } @@ -408,7 +395,7 @@ int start_userspace(unsigned long stub_stack) int unscheduled_userspace_iterations; extern unsigned long tt_extra_sched_jiffies; -void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs) +void userspace(struct uml_pt_regs *regs) { int err, status, op, pid = userspace_pid[0]; siginfo_t si; @@ -527,11 +514,11 @@ void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs) case SIGSEGV: if (PTRACE_FULL_FAULTINFO) { get_skas_faultinfo(pid, - ®s->faultinfo, aux_fp_regs); + ®s->faultinfo); (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si, regs); } - else handle_segv(pid, regs, aux_fp_regs); + else handle_segv(pid, regs); break; case SIGTRAP + 0x80: handle_trap(pid, regs); -- 2.46.2