On 23/06/2020 16:48, Richard Sandiford wrote:
Matthew Malcomson <matthew.malcom...@arm.com> writes:@@ -14466,6 +14466,81 @@ aarch64_validate_mcpu (const char *str, const struct processor **res, return false; mfix-cortex-a53-835769 Target Report Var(aarch64_fix_a53_err835769) Init(2) Save Workaround for ARM Cortex-A53 Erratum number 835769. diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 35e8242af5fa4c52744fd2c3e2cfee0a617e22bb..8a3fab2964c9bb06c820766d284768751d63ac9a 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -696,6 +696,7 @@ Objective-C and Objective-C++ Dialects}. -msign-return-address=@var{scope} @gol -mbranch-protection=@var{none}|@var{standard}|@var{pac-ret}[+@var{leaf} +@var{b-key}]|@var{bti} @gol +-mharden-sls=@var{none}|@var{all}|@var{retbr}|@var{blr} @gol -march=@var{name} -mcpu=@var{name} -mtune=@var{name} @gol -moverride=@var{string} -mverbose-cost-dump @gol -mstack-protector-guard=@var{guard} -mstack-protector-guard-reg=@var{sysreg} @gol @@ -17045,6 +17046,15 @@ functions. The optional argument @samp{b-key} can be used to sign the functions with the B-key instead of the A-key. @samp{bti} turns on branch target identification mechanism.+@item -mharden-sls=@var{none}|@var{all}|@var{retbr}|@var{blr}+@opindex mharden-sls +Enable compiler hardening against straight line speculation (SLS). +There are two options for hardening against straight line speculation. +@samp{retbr} allows inserting speculation barriers after every +@samp{br} and @samp{ret} instruction. While @samp{blr} enables replacing +@samp{blr} instructions with a @samp{bl} to a function stub. +@samp{all} enables all SLS hardening, while @samp{none} does not enable any.OK, so this is even more picky, sorry, but the syntax and description imply to me that you can choose only one of the four options. I think it would be more accurate to say something like: @item -mharden-sls=@var{opts} @opindex mharden-sls Enable compiler hardening against straight line speculation (SLS). @var{opts} is a comma-separated list of the following options: @table @samp @item retbr … @item blr … @end table In addition, @samp{-mharden-sls=all} enables all SLS hardening while @samp{-mharden-sls=none} disables all SLS hardening. (assuming the above behaviour change for “none”) Thanks, Richard
Another "just to check": the same change should be made in the short form right? (i.e. the hunk above is now `-mharden-sls=@var{opts}`)
