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u3: factors out individual page protections

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This commit is contained in:
Joe Bryan 2022-12-12 20:50:34 -05:00
parent 9fe6f3dde0
commit 4659b92d26
1 changed files with 40 additions and 40 deletions
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80
pkg/urbit/noun/events.c
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@ -167,7 +167,38 @@ u3e_check(c3_c* cap_c)
} }
#endif #endif
/* _ce_flaw_protect(): protect page after fault.
*/
static inline c3_i
_ce_flaw_protect(c3_w pag_w)
{
if ( 0 != mprotect((void *)(u3_Loom + (pag_w << u3a_page)),
pag_siz_i,
(PROT_READ | PROT_WRITE)) )
{
fprintf(stderr, "loom: fault mprotect (%u): %s\r\n",
pag_w, strerror(errno));
return 1;
}
return 0;
}
#ifdef U3_GUARD_PAGE #ifdef U3_GUARD_PAGE
/* _ce_ward_protect(): protect the guard page.
*/
static inline c3_i
_ce_ward_protect(void)
{
if ( 0 != mprotect(u3a_into(gar_pag_p), pag_siz_i, PROT_NONE) ) {
fprintf(stderr, "loom: failed to protect guard page (%u): %s\r\n",
gar_pag_p >> u3a_page, strerror(errno));
return 1;
}
return 0;
}
//! Place a guard page at the (approximate) middle of the free space between //! Place a guard page at the (approximate) middle of the free space between
//! the heap and stack of the current road, bailing if memory has been //! the heap and stack of the current road, bailing if memory has been
//! exhausted. //! exhausted.
@ -204,12 +235,7 @@ _ce_center_guard_page(void)
goto bail; goto bail;
} }
if ( -1 == mprotect(u3a_into(gar_pag_p), pag_siz_i, PROT_NONE) ) { if ( _ce_ward_protect() ) {
fprintf(stderr,
"loom: failed to protect the guard page "
"(base address %p): %s\r\n",
u3a_into(gar_pag_p),
strerror(errno));
goto fail; goto fail;
} }
@ -266,11 +292,7 @@ u3e_fault(void* adr_v, c3_i ser_i)
u3P.dit_w[blk_w] |= (1 << bit_w); u3P.dit_w[blk_w] |= (1 << bit_w);
if ( -1 == mprotect((void *)(u3_Loom + (pag_w << u3a_page)), if ( _ce_flaw_protect(pag_w) ) {
pag_siz_i,
(PROT_READ | PROT_WRITE)) )
{
fprintf(stderr, "loom: fault mprotect: %s\r\n", strerror(errno));
c3_assert(0); c3_assert(0);
return 0; return 0;
} }
@ -847,11 +869,7 @@ _ce_loom_protect_north(c3_w pgs_w, c3_w old_w)
// //
if ( (gar_pag_p >> u3a_page) < old_w ) { if ( (gar_pag_p >> u3a_page) < old_w ) {
fprintf(stderr, "loom: guard on reprotect\r\n"); fprintf(stderr, "loom: guard on reprotect\r\n");
if ( 0 != mprotect(u3a_into(gar_pag_p), pag_siz_i, PROT_NONE) ) { c3_assert( !_ce_ward_protect() );
fprintf(stderr, "loom: failed to protect guard page: %s\r\n",
strerror(errno));
c3_assert(0);
}
} }
#endif #endif
@ -898,11 +916,7 @@ _ce_loom_protect_south(c3_w pgs_w, c3_w old_w)
// //
if ( (gar_pag_p >> u3a_page) >= off_w ) { if ( (gar_pag_p >> u3a_page) >= off_w ) {
fprintf(stderr, "loom: guard on reprotect\r\n"); fprintf(stderr, "loom: guard on reprotect\r\n");
if ( 0 != mprotect(u3a_into(gar_pag_p), pag_siz_i, PROT_NONE) ) { c3_assert( !_ce_ward_protect() );
fprintf(stderr, "loom: failed to protect guard page: %s\r\n",
strerror(errno));
c3_assert(0);
}
} }
#endif #endif
@ -961,11 +975,7 @@ _ce_loom_mapf_north(c3_i fid_i, c3_w pgs_w, c3_w old_w)
// //
if ( (gar_pag_p >> u3a_page) < old_w ) { if ( (gar_pag_p >> u3a_page) < old_w ) {
fprintf(stderr, "loom: guard on remap\r\n"); fprintf(stderr, "loom: guard on remap\r\n");
if ( 0 != mprotect(u3a_into(gar_pag_p), pag_siz_i, PROT_NONE) ) { c3_assert( !_ce_ward_protect() );
fprintf(stderr, "loom: failed to protect guard page: %s\r\n",
strerror(errno));
c3_assert(0);
}
} }
#endif #endif
@ -1377,11 +1387,7 @@ u3e_yolo(void)
} }
#ifdef U3_GUARD_PAGE #ifdef U3_GUARD_PAGE
if ( 0 != mprotect(u3a_into(gar_pag_p), pag_siz_i, PROT_NONE) ) { c3_assert( !_ce_ward_protect() );
fprintf(stderr, "loom: failed to protect guard page: %s\r\n",
strerror(errno));
c3_assert(0);
}
#endif #endif
// mark all pages dirty // mark all pages dirty
@ -1401,6 +1407,8 @@ u3e_init(void)
#ifdef U3_GUARD_PAGE #ifdef U3_GUARD_PAGE
_ce_center_guard_page(); _ce_center_guard_page();
#endif #endif
_ce_loom_track_north(0, u3P.pag_w);
} }
/* u3e_ward(): reposition guard page if needed. /* u3e_ward(): reposition guard page if needed.
@ -1413,15 +1421,7 @@ u3e_ward(u3_post low_p, u3_post hig_p)
if ( (low_p > gar_p) || (hig_p < gar_p) ) { if ( (low_p > gar_p) || (hig_p < gar_p) ) {
_ce_center_guard_page(); _ce_center_guard_page();
c3_assert( !_ce_flaw_protect(gar_p >> u3a_page) );
if ( 0 != mprotect(u3a_into(gar_p),
pag_siz_i,
(PROT_READ | PROT_WRITE)) )
{
fprintf(stderr, "loom: failed to unprotect old guard page: %s\r\n",
strerror(errno));
c3_assert(0);
}
{ {
c3_w pag_w = gar_p >> u3a_page; c3_w pag_w = gar_p >> u3a_page;