From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id 3BDAE385800C for ; Tue, 10 Jan 2023 16:50:05 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 3BDAE385800C Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=foss.arm.com Authentication-Results: sourceware.org; spf=none smtp.mailfrom=foss.arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E8E732F4; Tue, 10 Jan 2023 08:50:46 -0800 (PST) Received: from [10.2.78.76] (unknown [10.2.78.76]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 739E83F67D; Tue, 10 Jan 2023 08:50:04 -0800 (PST) Message-ID: <860752db-3140-4240-7580-c34234e91c80@foss.arm.com> Date: Tue, 10 Jan 2023 16:50:03 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH v5b 8/8] newlib: libc: setjmp M-profile PACBTI-enablement Content-Language: en-GB To: "Victor L. Do Nascimento" , newlib@sourceware.org References: From: Richard Earnshaw In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-3495.7 required=5.0 tests=BAYES_00,GIT_PATCH_0,KAM_DMARC_STATUS,KAM_LAZY_DOMAIN_SECURITY,NICE_REPLY_A,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 10/01/2023 14:02, Victor L. Do Nascimento wrote: > This patch revision provides the following improvements to proposed > patch implementation: > * Load ip directly when restoring PAC code from stack for > authentication in longjmp epilogue. > * Improve code readability by defining the JUMPBUF_PAC macro to > map onto the otherwise obscure 104 constant used in str/ldr > instructions. > > Add function prologue/epilogue to conditionally add BTI landing pads > and/or PAC code generation & authentication instructions depending on > compilation flags. Thanks. I've now pushed the entire series. R. > --- > newlib/libc/machine/arm/setjmp.S | 43 ++++++++++++++++++++++++++++++++ > 1 file changed, 43 insertions(+) > > diff --git a/newlib/libc/machine/arm/setjmp.S b/newlib/libc/machine/arm/setjmp.S > index d814afea8..5213c063b 100644 > --- a/newlib/libc/machine/arm/setjmp.S > +++ b/newlib/libc/machine/arm/setjmp.S > @@ -22,6 +22,11 @@ > #define SIZE(x) > #endif > > +/* Jump buffer allocation sizes. */ > +#define JUMPBUF_CORE_REGS_SIZE (10 * 4) > +#define JUMPBUF_FP_REGS_SIZE (8 * 8) > +#define JUMPBUF_PAC (JUMPBUF_CORE_REGS_SIZE + JUMPBUF_FP_REGS_SIZE + 0) > + > /* Arm/Thumb interworking support: > > The interworking scheme expects functions to use a BX instruction > @@ -155,6 +160,8 @@ SYM (.arm_start_of.\name): > .align 2 > MODE > .globl SYM (\name) > + .fnstart > + .cfi_startproc > TYPE (\name) > SYM (\name): > PROLOGUE \name > @@ -162,6 +169,8 @@ SYM (\name): > > .macro FUNC_END name > RET > + .cfi_endproc > + .fnend > SIZE (\name) > .endm > > @@ -171,6 +180,21 @@ SYM (\name): > > FUNC_START setjmp > > +#if __ARM_FEATURE_PAC_DEFAULT > +# if __ARM_FEATURE_BTI_DEFAULT > + pacbti ip, lr, sp > +# else > + pac ip, lr, sp > +# endif /* __ARM_FEATURE_BTI_DEFAULT */ > + mov r3, ip > + str r3, [r0, #JUMPBUF_PAC] > + .cfi_register 143, 12 > +#else > +# if __ARM_FEATURE_BTI_DEFAULT > + bti > +# endif /* __ARM_FEATURE_BTI_DEFAULT */ > +#endif /* __ARM_FEATURE_PAC_DEFAULT */ > + > /* Save all the callee-preserved registers into the jump buffer. */ > #ifdef __thumb2__ > mov ip, sp > @@ -184,6 +208,10 @@ SYM (\name): > > /* When setting up the jump buffer return 0. */ > mov r0, #0 > +#if __ARM_FEATURE_PAC_DEFAULT > + mov ip, r3 > + aut ip, lr, sp > +#endif /* __ARM_FEATURE_PAC_DEFAULT */ > > FUNC_END setjmp > > @@ -193,6 +221,16 @@ SYM (\name): > > FUNC_START longjmp > > +#if __ARM_FEATURE_BTI_DEFAULT > + bti > +#endif /* __ARM_FEATURE_BTI_DEFAULT */ > + > +#if __ARM_FEATURE_PAC_DEFAULT > + /* Keep original jmpbuf address for retrieving pac-code > + for authentication. */ > + mov r2, r0 > +#endif /* __ARM_FEATURE_PAC_DEFAULT */ > + > /* If we have stack extension code it ought to be handled here. */ > > /* Restore the registers, retrieving the state when setjmp() was called. */ > @@ -212,5 +250,10 @@ SYM (\name): > it eq > moveq r0, #1 > > +#if __ARM_FEATURE_PAC_DEFAULT > + ldr ip, [r2, #JUMPBUF_PAC] > + aut ip, lr, sp > +#endif /* __ARM_FEATURE_PAC_DEFAULT */ > + > FUNC_END longjmp > #endif