• LEROY Christophe's avatar
    powerpc/8xx: Implementation of PAGE_EXEC · 5b2753fc
    LEROY Christophe authored
    This patch implements PAGE_EXEC capability on the 8xx.
    
    All pages PP exec bits are set to 000, which means Execute for
    Supervisor and no Execute for User.
    Then we use the APG to say whether accesses are according to Page
    rules, "all Supervisor" rules (Exec for all) and
    "all User" rules (Exec for noone)
    
    Therefore, we define 4 APG groups. msb is _PAGE_EXEC,
    lsb is _PAGE_USER. MI_AP is initialised as follows:
    GP0 (00) => Not User, no exec => 11 (all accesses performed as user)
    GP1 (01) => User but no exec => 11 (all accesses performed as user)
    GP2 (10) => Not User, exec => 01 (rights according to page definition)
    GP3 (11) => User, exec => 00 (all accesses performed as supervisor)
    Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
    [scottwood: comments: s/exec/data/ on data side, and s/pages/pages'/]
    Signed-off-by: default avatarScott Wood <scottwood@freescale.com>
    5b2753fc
head_8xx.S 27.1 KB