Date: Thu, 25 Feb 2021 21:32:15 GMT From: Mitchell Horne <mhorne@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 8f686c0f29f0 - releng/13.0 - arm64: handle watchpoint exceptions from EL0 Message-ID: <202102252132.11PLWFPl033511@gitrepo.freebsd.org>
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The branch releng/13.0 has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=8f686c0f29f094eba305d7911195bd629c3954bb commit 8f686c0f29f094eba305d7911195bd629c3954bb Author: Mitchell Horne <mhorne@FreeBSD.org> AuthorDate: 2021-02-05 21:46:48 +0000 Commit: Mitchell Horne <mhorne@FreeBSD.org> CommitDate: 2021-02-25 21:31:17 +0000 arm64: handle watchpoint exceptions from EL0 This is a prerequisite to allowing the use of hardware watchpoints for userspace debuggers. This is also a slight departure from the x86 behaviour, since `si_addr` returns the data address that triggered the watchpoint, not the address of the instruction that was executed. Otherwise, there is no straightforward way for the application to determine which watchpoint was triggered. Make a note of this in the siginfo(3) man page. Reviewed by: jhb, markj (earlier version) Tested by: Michał Górny (mgorny@gentoo.org) Sponsored by: The FreeBSD Foundation Approved by: re (gjb) (cherry picked from commit bd012c71592323d957b409bb5e0cf7940729650e) (cherry picked from commit 9372df63ad5b814440732d171c8f04f0e1c26b87) --- share/man/man3/siginfo.3 | 7 ++++++- sys/arm64/arm64/trap.c | 6 ++++++ sys/arm64/include/armreg.h | 1 + 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/share/man/man3/siginfo.3 b/share/man/man3/siginfo.3 index fc4ea2ba1df7..acc8785b2f0d 100644 --- a/share/man/man3/siginfo.3 +++ b/share/man/man3/siginfo.3 @@ -27,7 +27,7 @@ .\" .\" $FreeBSD$ .\" -.Dd July 28, 2020 +.Dd February 17, 2021 .Dt SIGINFO 3 .Os .Sh NAME @@ -218,6 +218,11 @@ and may report the address of the faulting memory access (if available) in .Va si_addr instead. +Additionally +.Dv SIGTRAP +raised by a hardware watchpoint exception may report the data address that +triggered the watchpoint in +.Va si_addr . .Pp Sychronous signals set .Va si_trapno diff --git a/sys/arm64/arm64/trap.c b/sys/arm64/arm64/trap.c index 0b2d4760cea3..cb3a05ad0163 100644 --- a/sys/arm64/arm64/trap.c +++ b/sys/arm64/arm64/trap.c @@ -474,6 +474,7 @@ do_el0_sync(struct thread *td, struct trapframe *frame) case EXCP_UNKNOWN: case EXCP_DATA_ABORT_L: case EXCP_DATA_ABORT: + case EXCP_WATCHPT_EL0: far = READ_SPECIALREG(far_el1); break; } @@ -534,6 +535,11 @@ do_el0_sync(struct thread *td, struct trapframe *frame) exception); userret(td, frame); break; + case EXCP_WATCHPT_EL0: + call_trapsignal(td, SIGTRAP, TRAP_TRACE, (void *)far, + exception); + userret(td, frame); + break; case EXCP_MSR: /* * The CPU can raise EXCP_MSR when userspace executes an mrs diff --git a/sys/arm64/include/armreg.h b/sys/arm64/include/armreg.h index 73d1010057b9..66cd8591c7ab 100644 --- a/sys/arm64/include/armreg.h +++ b/sys/arm64/include/armreg.h @@ -230,6 +230,7 @@ #define EXCP_BRKPT_EL0 0x30 /* Hardware breakpoint, from same EL */ #define EXCP_SOFTSTP_EL0 0x32 /* Software Step, from lower EL */ #define EXCP_SOFTSTP_EL1 0x33 /* Software Step, from same EL */ +#define EXCP_WATCHPT_EL0 0x34 /* Watchpoint, from lower EL */ #define EXCP_WATCHPT_EL1 0x35 /* Watchpoint, from same EL */ #define EXCP_BRK 0x3c /* Breakpoint */
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