Date: Tue, 22 Feb 2022 17:59:23 +0000 From: Jessica Clarke <jrtc27@freebsd.org> To: Andrew Turner <andrew@FreeBSD.org> Cc: "src-committers@freebsd.org" <src-committers@FreeBSD.org>, "dev-commits-src-all@freebsd.org" <dev-commits-src-all@FreeBSD.org>, "dev-commits-src-main@freebsd.org" <dev-commits-src-main@FreeBSD.org> Subject: Re: git: 6713be315900 - main - Add NT_ARM_ADDR_MASK Message-ID: <2C1219E1-9F36-4FDC-95B1-AD6DC9F0C215@freebsd.org> In-Reply-To: <202202221727.21MHR4dv022628@gitrepo.freebsd.org> References: <202202221727.21MHR4dv022628@gitrepo.freebsd.org>
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On 22 Feb 2022, at 17:27, Andrew Turner <andrew@FreeBSD.org> wrote: >=20 > The branch main has been updated by andrew: >=20 > URL: = https://cgit.FreeBSD.org/src/commit/?id=3D6713be3159000783f7aacf3ea90d6c68= 78c44da0 >=20 > commit 6713be3159000783f7aacf3ea90d6c6878c44da0 > Author: Andrew Turner <andrew@FreeBSD.org> > AuthorDate: 2021-08-30 16:43:22 +0000 > Commit: Andrew Turner <andrew@FreeBSD.org> > CommitDate: 2022-02-22 17:10:35 +0000 >=20 > Add NT_ARM_ADDR_MASK >=20 > This can be used by debuggers to find which bits in a virtual = address > should be masked off to get a canonical address. This is currently = used > by the Pointer Authentication Code support to get its mask. It = could also > be used if we support Top Byte Ignore for the same purpose. >=20 > Reviewed by: kib > Sponsored by: The FreeBSD Foundation > Differential Revision: https://reviews.freebsd.org/D34302 This definition seems backwards? In Linux it=E2=80=99s NT_ARM_PAC_MASK, = i.e. the mask for the PAC bits, but you=E2=80=99ve called it NT_ARM_ADDR_MASK = here, which sounds like the mask you apply to get the address bits, but it=E2=80= =99s not, you apply the negation of this mask to get the address bits. Jess > --- > sys/arm64/arm64/elf_machdep.c | 42 = ++++++++++++++++++++++++++++++++++++++++-- > sys/arm64/arm64/ptrauth.c | 8 +++++++- > sys/arm64/include/cpu.h | 3 +++ > sys/arm64/include/reg.h | 5 +++++ > sys/arm64/include/vmparam.h | 3 +++ > sys/sys/elf_common.h | 1 + > tests/sys/kern/ptrace_test.c | 13 +++++++++++++ > 7 files changed, 72 insertions(+), 3 deletions(-) >=20 > diff --git a/sys/arm64/arm64/elf_machdep.c = b/sys/arm64/arm64/elf_machdep.c > index d98512b71e6c..383a0911b7fe 100644 > --- a/sys/arm64/arm64/elf_machdep.c > +++ b/sys/arm64/arm64/elf_machdep.c > @@ -59,6 +59,8 @@ __FBSDID("$FreeBSD$"); > u_long __read_frequently elf_hwcap; > u_long __read_frequently elf_hwcap2; >=20 > +struct arm64_addr_mask elf64_addr_mask; > + > static struct sysentvec elf64_freebsd_sysvec =3D { > .sv_size =3D SYS_MAXSYSCALL, > .sv_table =3D sysent, > @@ -119,11 +121,47 @@ static Elf64_Brandinfo freebsd_brand_info =3D { > SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_FIRST, > (sysinit_cfunc_t)elf64_insert_brand_entry, &freebsd_brand_info); >=20 > +static bool > +get_arm64_addr_mask(struct regset *rs, struct thread *td, void *buf, > + size_t *sizep) > +{ > + if (buf !=3D NULL) { > + KASSERT(*sizep =3D=3D sizeof(elf64_addr_mask), > + ("%s: invalid size", __func__)); > + memcpy(buf, &elf64_addr_mask, sizeof(elf64_addr_mask)); > + } > + *sizep =3D sizeof(elf64_addr_mask); > + > + return (true); > +} > + > +static struct regset regset_arm64_addr_mask =3D { > + .note =3D NT_ARM_ADDR_MASK, > + .size =3D sizeof(struct arm64_addr_mask), > + .get =3D get_arm64_addr_mask, > +}; > +ELF_REGSET(regset_arm64_addr_mask); > + > void > -elf64_dump_thread(struct thread *td __unused, void *dst __unused, > - size_t *off __unused) > +elf64_dump_thread(struct thread *td, void *dst, size_t *off) > { > + struct arm64_addr_mask addr_mask; > + size_t len, mask_size; > + > + len =3D 0; > + if (dst !=3D NULL) { > + mask_size =3D sizeof(addr_mask); > + get_arm64_addr_mask(®set_arm64_addr_mask, td, = &addr_mask, > + &mask_size); > + > + len +=3D elf64_populate_note(NT_ARM_ADDR_MASK, = &addr_mask, dst, > + sizeof(addr_mask), NULL); > + } else { > + len +=3D elf64_populate_note(NT_ARM_ADDR_MASK, NULL, = NULL, > + sizeof(addr_mask), NULL); > + } >=20 > + *off +=3D len; > } >=20 > bool > diff --git a/sys/arm64/arm64/ptrauth.c b/sys/arm64/arm64/ptrauth.c > index aa0591e351bb..5c129820cd37 100644 > --- a/sys/arm64/arm64/ptrauth.c > +++ b/sys/arm64/arm64/ptrauth.c > @@ -46,6 +46,8 @@ __FBSDID("$FreeBSD$"); >=20 > #include <machine/armreg.h> > #include <machine/cpu.h> > +#include <machine/reg.h> > +#include <machine/vmparam.h> >=20 > #define SCTLR_PTRAUTH (SCTLR_EnIA | SCTLR_EnIB | SCTLR_EnDA | = SCTLR_EnDB) >=20 > @@ -82,8 +84,12 @@ ptrauth_init(void) > * it will also be available on any non-boot CPUs. If this is = ever > * not the case we will have to add a quirk. > */ > - if (ID_AA64ISAR1_APA_VAL(isar1) > 0 || = ID_AA64ISAR1_API_VAL(isar1) > 0) > + if (ID_AA64ISAR1_APA_VAL(isar1) > 0 || > + ID_AA64ISAR1_API_VAL(isar1) > 0) { > enable_ptrauth =3D true; > + elf64_addr_mask.code |=3D PAC_ADDR_MASK; > + elf64_addr_mask.data |=3D PAC_ADDR_MASK; > + } > } >=20 > /* Copy the keys when forking a new process */ > diff --git a/sys/arm64/include/cpu.h b/sys/arm64/include/cpu.h > index a6a606b58912..d3b13470a9be 100644 > --- a/sys/arm64/include/cpu.h > +++ b/sys/arm64/include/cpu.h > @@ -164,6 +164,9 @@ extern char etext[]; >=20 > extern uint64_t __cpu_affinity[]; >=20 > +struct arm64_addr_mask; > +extern struct arm64_addr_mask elf64_addr_mask; > + > void cpu_halt(void) __dead2; > void cpu_reset(void) __dead2; > void fork_trampoline(void); > diff --git a/sys/arm64/include/reg.h b/sys/arm64/include/reg.h > index bb151af55ba6..44b2e2b21b72 100644 > --- a/sys/arm64/include/reg.h > +++ b/sys/arm64/include/reg.h > @@ -83,6 +83,11 @@ struct dbreg32 { > int dummy; > }; >=20 > +struct arm64_addr_mask { > + __uint64_t code; > + __uint64_t data; > +}; > + > #define __HAVE_REG32 >=20 > #endif /* !_MACHINE_REG_H_ */ > diff --git a/sys/arm64/include/vmparam.h b/sys/arm64/include/vmparam.h > index 3e08b0a513b9..483c6d1f91a2 100644 > --- a/sys/arm64/include/vmparam.h > +++ b/sys/arm64/include/vmparam.h > @@ -156,6 +156,9 @@ > #define VM_MIN_KERNEL_ADDRESS (0xffff000000000000UL) > #define VM_MAX_KERNEL_ADDRESS (0xffff008000000000UL) >=20 > +/* The address bits that hold a pointer authentication code */ > +#define PAC_ADDR_MASK (0xff7f000000000000UL) > + > /* If true addr is in the kernel address space */ > #define ADDR_IS_KERNEL(addr) (((addr) & (1ul << 55)) =3D=3D = (1ul << 55)) > /* If true addr is in its canonical form (i.e. no TBI, PAC, etc.) */ > diff --git a/sys/sys/elf_common.h b/sys/sys/elf_common.h > index b8629fec8cbc..0bc93659adc5 100644 > --- a/sys/sys/elf_common.h > +++ b/sys/sys/elf_common.h > @@ -825,6 +825,7 @@ typedef struct { > #define NT_PPC_VSX 0x102 /* PowerPC VSX registers */ > #define NT_X86_XSTATE 0x202 /* x86 XSAVE extended state. */ > #define NT_ARM_VFP 0x400 /* ARM VFP registers */ > +#define NT_ARM_ADDR_MASK 0x406 /* arm64 address mask = (e.g. for TBI) */ >=20 > /* GNU note types. */ > #define NT_GNU_ABI_TAG 1 > diff --git a/tests/sys/kern/ptrace_test.c = b/tests/sys/kern/ptrace_test.c > index 3e3a445c6152..c62db66fd6f6 100644 > --- a/tests/sys/kern/ptrace_test.c > +++ b/tests/sys/kern/ptrace_test.c > @@ -3204,6 +3204,9 @@ = ATF_TC_BODY(ptrace__PT_CONTINUE_with_signal_thread_sigmask, tc) > ATF_TC_WITHOUT_HEAD(ptrace__PT_REGSET); > ATF_TC_BODY(ptrace__PT_REGSET, tc) > { > +#if defined(__aarch64__) > + struct arm64_addr_mask addr_mask; > +#endif > struct prstatus prstatus; > struct iovec vec; > pid_t child, wpid; > @@ -3242,6 +3245,16 @@ ATF_TC_BODY(ptrace__PT_REGSET, tc) > ATF_REQUIRE(ptrace(PT_SETREGSET, wpid, (caddr_t)&vec, = NT_PRSTATUS) !=3D > -1); >=20 > +#if defined(__aarch64__) > + vec.iov_base =3D &addr_mask; > + vec.iov_len =3D sizeof(addr_mask); > + ATF_REQUIRE(ptrace(PT_GETREGSET, wpid, (caddr_t)&vec, > + NT_ARM_ADDR_MASK) !=3D -1); > + REQUIRE_EQ(addr_mask.code, addr_mask.data); > + ATF_REQUIRE(addr_mask.code =3D=3D 0 || > + addr_mask.code =3D=3D 0xff7f000000000000UL); > +#endif > + > REQUIRE_EQ(ptrace(PT_CONTINUE, child, (caddr_t)1, 0), 0); >=20 > /* The second wait() should report the exit status. */
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