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Shutemov" To: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , Ard Biesheuvel , "Paul E. McKenney" , Josh Poimboeuf , Xiongwei Song , Xin Li , "Mike Rapoport (IBM)" , Brijesh Singh , Michael Roth , Tony Luck , Alexey Kardashevskiy , Alexander Shishkin Cc: Jonathan Corbet , Sohil Mehta , Ingo Molnar , Pawan Gupta , Daniel Sneddon , Kai Huang , Sandipan Das , Breno Leitao , Rick Edgecombe , Alexei Starovoitov , Hou Tao , Juergen Gross , Vegard Nossum , Kees Cook , Eric Biggers , Jason Gunthorpe , "Masami Hiramatsu (Google)" , Andrew Morton , Luis Chamberlain , Yuntao Wang , Rasmus Villemoes , Christophe Leroy , Tejun Heo , Changbin Du , Huang Shijie , Geert Uytterhoeven , Namhyung Kim , Arnaldo Carvalho de Melo , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" Subject: [PATCHv6 13/16] x86/traps: Handle LASS thrown #SS Date: Fri, 20 Jun 2025 16:53:21 +0300 Message-ID: <20250620135325.3300848-14-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.47.2 In-Reply-To: <20250620135325.3300848-1-kirill.shutemov@linux.intel.com> References: <20250620135325.3300848-1-kirill.shutemov@linux.intel.com> Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Alexander Shishkin LASS throws a #GP for any violations except for stack register accesses, in which case it throws a #SS instead. Handle this similarly to how other LASS violations are handled. Signed-off-by: Alexander Shishkin Signed-off-by: Kirill A. Shutemov --- arch/x86/kernel/traps.c | 34 ++++++++++++++++++++++++++++------ 1 file changed, 28 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 0f558d3369a3..bd8f7e72b238 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -418,12 +418,6 @@ DEFINE_IDTENTRY_ERRORCODE(exc_segment_not_present) SIGBUS, 0, NULL); } -DEFINE_IDTENTRY_ERRORCODE(exc_stack_segment) -{ - do_error_trap(regs, error_code, "stack segment", X86_TRAP_SS, SIGBUS, - 0, NULL); -} - DEFINE_IDTENTRY_ERRORCODE(exc_alignment_check) { char *str = "alignment check"; @@ -866,6 +860,34 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection) cond_local_irq_disable(regs); } +DEFINE_IDTENTRY_ERRORCODE(exc_stack_segment) +{ + if (cpu_feature_enabled(X86_FEATURE_LASS)) { + enum kernel_gp_hint hint = GP_NO_HINT; + unsigned long gp_addr; + + if (user_mode(regs)) { + gp_user_force_sig_segv(regs, X86_TRAP_GP, error_code, GPFSTR); + return; + } + + hint = get_kernel_gp_address(regs, &gp_addr); + if (hint != GP_NO_HINT) { + printk(GPFSTR ", %s 0x%lx", kernel_gp_hint_help[hint], + gp_addr); + } + + if (hint != GP_NON_CANONICAL) + gp_addr = 0; + + die_addr(GPFSTR, regs, error_code, gp_addr); + return; + } + + do_error_trap(regs, error_code, "stack segment", X86_TRAP_SS, SIGBUS, + 0, NULL); +} + static bool do_int3(struct pt_regs *regs) { int res;